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DEPARTMENT OF DEFENSE
LAW OF WAR MANUAL
JUNE 2015
OFFICE OF GENERAL COUNSEL
DEPARTMENT OF DEFENSE
FOREWORD
The law of war is of fundamental importance to the Armed Forces of the United States.
The law of war is part of who we are. George Washington, as Commander in Chief of
the Continental Army, agreed with his British adversary that the Revolutionary War would be
“carried on agreeable to the rules which humanity formed” and “to prevent or punish every
breach of the rules of war within the sphere of our respective commands.” During the Civil War,
President Lincoln approved a set of “Instructions for the Government of the Armies of the
United States in the Field,” which inspired other countries to adopt similar codes for their armed
forces, and which served as a template for international codifications of the law of war.
After World War II, U.S. military lawyers, trying thousands of defendants before military
commissions did, in the words of Justice Robert Jackson, “stay the hand of vengeance and
voluntarily submit their captive enemies to the judgment of law” in “one of the most significant
tributes that Power has ever paid to Reason.” Reflecting on this distinctive history, one
Chairman of the Joint Chiefs of Staff observed that “[t]he laws of war have a peculiarly
American cast.” And it is also true that the laws of war have shaped the U.S. Armed Forces as
much as they have shaped any other armed force in the world.
The law of war is a part of our military heritage, and obeying it is the right thing to do.
But we also know that the law of war poses no obstacle to fighting well and prevailing. Nations
have developed the law of war to be fundamentally consistent with the military doctrines that are
the basis for effective combat operations. For example, the self-control needed to refrain from
violations of the law of war under the stresses of combat is the same good order and discipline
necessary to operate cohesively and victoriously in battle. Similarly, the law of war’s
prohibitions on torture and unnecessary destruction are consistent with the practical insight that
such actions ultimately frustrate rather than accomplish the mission.
This manual reflects many years of labor and expertise, on the part of civilian and
military lawyers from every Military Service. It reflects the experience of this Department in
applying the law of war in actual military operations, and it will help us remember the hard-
learned lessons from the past. Understanding our duties imposed by the law of war and our
rights under it is essential to our service in the nation’s defense.
Stephen W. Preston
General Counsel of the Department of Defense
ii
PREFACE
This manual is a Department of Defense (DoD)-wide resource for DoD personnel -
including commanders, legal practitioners, and other military and civilian personnel - on the law
of war.
This manual has many distinguished antecedents that have provided important guidance
to the U.S. Armed Forces. For example, General Order No. 100, the Instructions for the
Government of Armies of the United States in the Field, commonly known as the Lieber Code,
was prepared by Professor Francis Lieber and approved by President Abraham Lincoln during
the Civil War in 1863.1 A similar code related to naval warfare titled The Law and Usages of
War at Sea: A Naval War Code was prepared by then-Captain Charles H. Stockton and
approved by President William McKinley in 1900.2 The War Department published instructions
for the armed land forces of the United States in a 1914 manual titled Rules of Land Warfare,
which was updated in 1917, 1934, and 1940.3
After World War II, in connection with U.S. ratification of the 1949 Geneva
Conventions, the Department of the Navy published Naval Warfare Information Publication 10-
2, Law of Naval Warfare, in 1955,4 and the Department of the Army published Field Manual 27-
10, The Law of Land Warfare, in 1956, which was updated in 1976.5 The Department of the
Army also published pamphlets on international law applicable in peace and war in the 1960s,
and, in 1979, an updated version of the pamphlet on the law of peace.6 The Department of the
Air Force published in 1976 Air Force Pamphlet 110-31, International Law - The Conduct of
Armed Conflict and Air Operations, which was updated in 1980.7 More recently, the Judge
Advocate General of the Air Force’s School has published a manual titled Air Force Operations
and the Law in 2002, with new editions in 2009 and 2014.8 The Navy, Marine Corps, and Coast
1 E. D. Townsend, Assistant Adjutant General, General Orders No. 100, Instructions for the Government of Armies
of the United States in the Field, Apr. 24, 1863, reprinted in INSTRUCTIONS FOR THE GOVERNMENT OF ARMIES OF
THE UNITED STATES IN THE FIELD (Government Printing Office, 1898).
2 John D. Long, Secretary of the Navy, General Orders No. 551, The Laws and Usages of War at Sea, Jun. 27, 1900,
reprinted as Appendix I in U.S. Naval War College, International Law Discussions, 1903: The United States Naval
War Code of 1900, 101 (1904).
3 War Department, Office of the Chief of Staff, Rules of Land Warfare (Apr. 25, 1914); War Department, Office of
the Chief of Staff, Rules of Land Warfare (Apr. 25, 1914 with Changes Nos. 1 and 2, corrected to Apr. 15, 1917);
War Department, Basic Field Manual, Volume VII, Military Law, Part Two: Rules of Land Warfare (Jan. 2, 1934);
War Department Field Manual 27-10, Rules of Land Warfare (Oct. 1, 1940).
4 Department of the Navy, Office of the Chief of Naval Operations, Naval Warfare Information Publication 10-2,
Law of Naval Warfare (Sept. 1955), reprinted as Appendix in ROBERT W. TUCKER, THE LAW OF WAR AND
NEUTRALITY AT SEA (U.S. Naval War College International Law Studies, Volume 50, 1955).
5 Department of the Army Field Manual 27-10, The Law of Land Warfare (Jul. 18, 1956 with Change 1, Jul. 15,
1976).
6 Department of the Army Pamphlet 27-161-2, II International Law (Oct. 23, 1962); Department of the Army
Pamphlet 27-161-1, I International Law: The Law of Peace (Sept. 1, 1979).
7 Department of the Air Force Pamphlet 110-31, International Law - The Conduct of Armed Conflict and Air
Operations (Nov. 19, 1976).
iii
Guard have published several editions of The Commander’s Handbook on the Law of Naval
Operations starting in 1987 and most recently in 2007.9 Helpful annotated supplements have
also been published.10
In addition to these major publications, DoD components have produced many other
publications that have supported DoD lawyers in giving advice on the law of war. For example,
since 1895, the Naval War College has published its International Law Studies journal.11 The
Judge Advocate General of the Army’s Legal Center & School has published many editions of a
Law of Armed Conflict Deskbook, a Law of Armed Conflict Documentary Supplement, and an
Operational Law Handbook.12
The preparation of this manual also has benefited greatly from consulting foreign experts
and resources - for example, the 2004 edition of the Manual of the Law of Armed Conflict by
United Kingdom Ministry of Defence.13 In this way, the preparation of this manual is no
different from its predecessors. For example, the 1956 Army Field manual benefited from
considering a draft of what ultimately became the 1958 United Kingdom law of war manual, and
the preparation of the 1914 War Department manual benefited from the Rules of Land Warfare
prepared by officers of the English Army and Professor Lassa Oppenheim.14 The law of war
8 Department of the Air Force, The Judge Advocate General’s School, Air Force Operations and the Law (3rd ed.,
2014); Department of the Air Force, The Judge Advocate General’s School, Air Force Operations & the Law: A
Guide for Air, Space, and Cyber Forces (2nd ed., 2009); Department of the Air Force, Office of the Judge Advocate
General, Air Force Operations & the Law (1st ed., 2002).
9 Department of the Navy, Naval Warfare Publication 9, The Commander’s Handbook on the Law of Naval
Operations (Jul. 1987); Department of the Navy, Naval Warfare Publication 1-14M / Marine Corps Warfighting
Publication 5-2.1 / Commandant Publication P5800.1, The Commander’s Handbook on the Law of Naval
Operations (Oct. 1995); Department of the Navy, Naval Warfare Publication 1-14M / Marine Corps Warfighting
Publication 5-12.1 / Commandant Publication P5800.7A, The Commander’s Handbook on the Law of Naval
Operations (Jul. 2007).
10 Department of the Navy, Office of the Judge Advocate General, Annotated Supplement to the Commander’s
Handbook on the Law of Naval Operations, NWP (Rev.A)/FMFM 1-10 (1989); U.S. Naval War College, Center for
Naval Warfare Studies, Oceans Law and Policy Department, Annotated Supplement to the Commander’s Handbook
on the Law of Naval Operations (1997).
11 See, e.g., U.S. Naval War College, International Law Studies, Vol. 88, Non-International Armed Conflict in the
Twenty-first Century (2012).
12 See, e.g., The Judge Advocate General’s Legal Center and School, U.S. Army, International and Operational Law
Department, Law of Armed Conflict Deskbook (2014); The Judge Advocate General’s Legal Center and School, U.S.
Army, International and Operational Law Department, Law of Armed Conflict Documentary Supplement (2014);
The Judge Advocate General’s Legal Center and School, U.S. Army, International and Operational Law
Department, Operational Law Handbook (2014).
13 United Kingdom Ministry of Defence, Joint Service Publication 383, The Joint Service Manual of the Law of
Armed Conflict (2004).
14 See War Department, Office of the Chief of Staff, Rules of Land Warfare, Preface 7 (Apr. 25, 1914) (“Especial
use was made of the Rules of Land Warfare, prepared by officers of the English Army and Prof. L. Oppenheim,
LL.D., and of Prof. Nagao Ariga’s book, ‘La Guerre Russo-Japonaise,’ which deals so carefully and thoroughly with
the laws and usages of war during one of the greatest wars of recent times.”).
iv
manuals of Germany, Australia, and Canada were also helpful resources in the preparation of this
manual.15
The preparation of this manual has also benefited from the participation of officers from
the United Kingdom’s Royal Air Force and the Australian Royal Air Force on exchange
assignments with the U.S. Air Force. In addition, military lawyers from Canada, the United
Kingdom, New Zealand, and Australia reviewed and commented on a draft of the manual in
2009 as part of review that also included comments from distinguished scholars.
Promulgating a DoD-wide manual on the law of war has been a long-standing goal of
DoD lawyers. Memoranda and meeting notes from the 1970s reflect that the international law
offices of the Department of the Army’s Office of the Judge Advocate General and the
Department of the Navy’s Office of the Judge Advocate General generally agreed on a concept
plan for a new all-Services law of war manual that would be a resource for implementing the
1977 Additional Protocols to the 1949 Geneva Conventions.16 At the time, it was anticipated
that the United States would ratify the Protocols, which has not occurred.
The origin of this manual may be traced to work in the late 1980s to update Department
of the Army Field Manual 27-10, The Law of Land Warfare.17 Then, in the mid-1990s, work
began on an all-Services law of war manual to reflect the views of all DoD components. It was
envisioned that the manual would provide not only the black letter rules, but also discussion,
examples of State practice, and references to past manuals, treatises, and other documents to
provide explanation, clarification, and elaboration. The present manual has sought to realize that
vision and thus it falls within the tradition of the 1914 War Department manual, as well as the
1989 and 1997 Commander’s Handbook on the Law of Naval Operations, which also adopted
this general approach of an annotated manual.
This manual is an institutional publication and reflects the views of the Department of
Defense, rather than the views of any particular person or DoD component. An effort has been
made to reflect in this manual sound legal positions based on relevant authoritative sources of the
law, including as developed by the DoD or the U.S. Government under such sources, and to
show in the cited sources the past practice of DoD or the United States in applying the law of
war.
This manual primarily has been prepared by the DoD Law of War Working Group, which
is chaired by a representative of the DoD General Counsel and includes representatives of the
15 Germany, Federal Ministry of Defence, Joint Service Regulation (ZDv) 15/2, Law of Armed Conflict Manual
(May 1, 2013); Australian Defence Force, Australian Defence Doctrine Publication 06.4, Law of Armed Conflict
(May 11, 2006); Canada, Department of National Defence, Joint Doctrine Manual B-GJ-005-104/FP-021, Law of
Armed Conflict at the Operational and Tactical Levels (Aug. 13, 2001).
16 Captain Bruce A. Harlow, JAGC, U.S. Navy, Memorandum for Mr. Waldemar H. Solf (DAJA-IA), Preparation
of New Law of War Manual (Dec. 28, 1976).
17 Remarks by W. Hays Parks, Customary Law and Additional Protocol I to the Geneva Conventions for Protection
of War Victims: Future Directions in Light of the U.S. Decision Not to Ratify, 81 AMERICAN SOCIETY OF
INTERNATIONAL LAW PROCEEDINGS 26 (Apr. 9, 1987) (“I have the job of writing the new U.S. Army Field Manual
27-10, The Law of Land Warfare, so this panel is of particular interest to me.”).
v
Judge Advocates General of the Army, Navy, and Air Force; the Staff Judge Advocate to the
Commandant of the Marine Corps; the offices of the General Counsels of the Military
Departments; and the Legal Counsel to the Chairman of the Joint Chiefs of Staff.18 This manual
has been reviewed by principals of these offices. The preparation of this manual has also
benefited significantly from the participation of experts from the Department of State, Office of
the Legal Adviser, and the Department of Justice, Office of Legal Counsel, although the views in
this manual do not necessarily reflect the views of those Departments or the U.S. Government as
a whole.
Comments and suggestions from users of the DoD Law of War Manual are invited. All
such correspondence should be addressed by email to:
osd.pentagon.ogc.mbx.ia-law-of-war-manual-comments@mail.mil.
18 Department of Defense Directive 2310.01E, DoD Law of War Program ¶5.1.4 (May 9, 2006, Certified Current as
of Feb. 22, 2011) (providing for a “DoD Law of War Working Group, consisting of representatives, at the election
by each of the GC, DoD; the General Counsel of each Military Department; the Counsel to the Commandant of the
Marine Corps; the Judge Advocate General of each Military Department; the Staff Judge Advocate to the
Commandant of the Marine Corps; and the Legal Counsel to the Chairman of the Joint Chiefs of Staff. The DoD
Law of War Working Group shall develop and coordinate law of war initiatives and issues; support the research,
preparation, review, and updating of the DoD Law of War Manual; manage other law of war matters as they arise;
and provide advice to the General Counsel on legal matters covered by this Directive.”).
vi
TABLE OF CONTENTS
Foreword
ii
Preface
iii
Table of Contents
vii
List of Abbreviations
xvii
I - General Background
1
1.1 Purpose and Scope of This Manual
1
1.2 Use of Footnotes, Sources, Cross-References, and Signals in This Manual
2
1.3 Definition of the Law of War
7
1.4 Object and Nature of War
15
1.5 “War” as a Legal Concept
18
1.6 Law of War Distinguished From Certain Topics
20
1.7 Treaties
27
1.8 Customary International Law
29
1.9 Subsidiary Means of Determining International Law
34
1.10 Legal Force of the Law of War
36
1.11 Jus ad Bellum
39
II - Principles
50
2.1 Introduction
50
2.2 Military Necessity
52
2.3 Humanity
58
2.4 Proportionality
60
2.5 Distinction
62
2.6 Honor
66
III - Application of the Law of War
70
3.1 Introduction
70
3.2 Situations to Which the Law of War Applies
73
3.3 Status of the Parties and the Law of War
73
3.4 When Jus in Bello Rules Apply
78
3.5 Relationship Between Jus in Bello and Jus ad Bellum
86
3.6 Reciprocity and Law of War Rules
89
3.7 Applying Rules by Analogy
92
3.8 End of Hostilities and the Application of the Law of War
94
3.9 Law of War Duties Also Applicable in Peace
96
IV - Classes of Persons
98
4.1 Introduction
98
vii
4.2 The Armed Forces and the Civilian Population
100
4.3 Lawful Combatants and Unprivileged Belligerents
103
4.4 Rights, Duties, and Liabilities of Combatants
106
4.5 Armed Forces of a State
112
4.6 Other Militia and Volunteer Corps
118
4.7 Levée en Masse
125
4.8 Rights, Duties, and Liabilities of Civilians
127
4.9 Military Medical and Religious Personnel
129
4.10 Rights, Duties, and Liabilities of Military Medical and Religious Personnel
133
4.11 Authorized Staff of Voluntary Aid Societies
134
4.12 Staff of a Recognized Aid Society of a Neutral Country
135
4.13 Auxiliary Medical Personnel
136
4.14 Personnel Engaged in Duties Related to the Protection of Cultural Property
138
4.15 Persons Authorized to Accompany the Armed Forces
142
4.16 Crews of Merchant Marine Vessels or Civil Aircraft
148
4.17 Spies, Saboteurs, and Other Persons Engaging in Similar Acts Behind
Enemy Lines
150
4.18 Private Persons Who Engage in Hostilities
157
4.19 Rights, Duties, and Liabilities of Unprivileged Belligerents
162
4.20 Children
166
4.21 Mercenaries
170
4.22 AP I Provisions on Civil Defense Personnel
172
4.23 Law Enforcement Officers
172
4.24 Journalists
173
4.25 Delegates or Representatives of the Protecting Powers
175
4.26 ICRC and Other Impartial Humanitarian Organizations
176
4.27 Determining the Status of Detainees in Cases of Doubt
179
V - The Conduct of Hostilities
183
5.1 Introduction
183
5.2 Principles for the Conduct of Hostilities
185
5.3 Overview of Rules for the Protection of Civilians
185
5.4 Assessing Information Under the Law of War
192
5.5 Rules on Conducting Assaults, Bombardments, and Other Attacks
194
5.6 Discrimination in Conducting Attacks
203
5.7 Military Objectives
205
5.8 Combatants
216
5.9 Civilians Taking a Direct Part in Hostilities
222
5.10 Persons Placed Hors de Combat
232
5.11 Feasible Precautions in Conducting Attacks to Reduce the Risk of Harm to
Protected Persons and Objects
237
5.12 Proportionality in Conducting Attacks
241
5.13 Attacks on Facilities, Works, or Installations Containing Dangerous Forces
247
5.14 Feasible Precautions to Reduce the Risk of Harm to Protected Persons and
Objects by the Party Subject to Attack
248
viii
5.15 Undefended Cities, Towns, and Villages
253
5.16 Prohibition on Using Protected Persons and Objects to Shield, Favor, or
Impede Military Operations
258
5.17 Seizure and Destruction of Enemy Property
261
5.18 Protection of Cultural Property During Hostilities
269
5.19 Sieges and Encircled Areas
288
5.20 Starvation
291
5.21 Overview of Good Faith, Perfidy, and Ruses
294
5.22 Treachery or Perfidy Used to Kill or Wound
296
5.23 Use of Enemy Flags, Insignia, and Military Uniforms
298
5.24 Improper Use of Certain Signs
300
5.25 Ruses of War and Other Lawful Deceptions
302
5.26 Non-Forcible Means and Methods of Warfare
307
5.27 Prohibition Against Compelling Enemy Nationals to Take Part in the
Operations of War Directed Against Their Own Country
310
VI - Weapons
312
6.1 Introduction
312
6.2 DoD Policy of Reviewing the Legality of Weapons
313
6.3 Other Practices to Help Implement Law of War Obligations With Respect to
Weapons
316
6.4 Prohibited Weapons
317
6.5 Lawful Weapons
318
6.6 Weapons Calculated to Cause Superfluous Injury
334
6.7 Inherently Indiscriminate Weapons
340
6.8 Poison, Poisoned Weapons, Poisonous Gases, and Other Chemical Weapons
343
6.9 Biological Weapons
350
6.10 Certain Environmental Modification Techniques
352
6.11 Weapons Injuring by Fragments Not Detectable by X-Rays
355
6.12 Landmines, Booby-Traps, and Other Devices
356
6.13 Cluster Munitions
380
6.14 Incendiary Weapons
382
6.15 Laser Weapons
387
6.16 Riot Control Agents
389
6.17 Herbicides
392
6.18 Nuclear Weapons
393
6.19 Explosive Ordnance
395
6.20 Explosive Remnants of War
400
VII -Wounded, Sick, Shipwrecked, Dead, and the Medical Services
410
7.1 Introduction
410
7.2 Application of the Protections of the GWS and GWS-Sea
413
7.3 Respect and Protection of the Wounded, Sick, and Shipwrecked
415
ix
7.4 Search, Collection, and Affirmative Protection of the Wounded, Sick,
Shipwrecked, and Dead
420
7.5 Humane Treatment and Care of Enemy Military Wounded, Sick, and
Shipwrecked in the Power of a Party to the Conflict
424
7.6 Accountability Information From the Enemy Military Wounded, Sick,
Shipwrecked, and Dead
428
7.7 Treatment and Handling of Enemy Military Dead
430
7.8 Respect and Protection of Categories of Medical and Religious Personnel
435
7.9 Captured Medical and Religious Personnel
438
7.10 Military Medical Units and Facilities
444
7.11 Ground Transports of the Wounded and Sick, or of Medical Equipment
451
7.12 Hospital Ships, Sick-Bays in Warships, and Coastal Rescue Craft
453
7.13 Chartered Medical Transport Ships
465
7.14 Military Medical Aircraft
466
7.15 Display of the Distinctive Emblem to Facilitate Identification
470
7.16 Protection of Civilians Who Are Wounded, Sick, Infirm, or Expectant
Mothers
477
7.17 Civilian Hospitals and Their Personnel
478
7.18 Land and Sea Civilian Hospital Convoys
481
7.19 Civilian Medical Aircraft
482
7.20 AP I Provisions on the Wounded, Sick, and Shipwrecked
483
VIII - Detention: Overview and Baseline Rules
486
8.1 Introduction
486
8.2 Humane Treatment of Detainees
492
8.3 Security Measures
495
8.4 Interrogation
496
8.5 Adequate Food, Drinking Water, and Clothing
497
8.6 General Conditions of Detention Facilities
497
8.7 Segregation of Detainees
498
8.8 Medical Attention
499
8.9 Administration and Discipline in Detention Facilities
500
8.10 Contacts With the Outside World
500
8.11 Religious Exercise
501
8.12 Intellectual, Physical, and Recreational Activities
502
8.13 Adequate Working Conditions
503
8.14 Procedures for Detention
503
8.15 National Accountability for Detention
506
8.16 Criminal Procedure and Punishment
508
IX - Prisoners of War (POWs)
511
9.1 Introduction
512
9.2 General Principles Applicable to the Treatment of POWs
515
9.3 POW Status
517
x
9.4 National-Level GPW Implementation Measures
522
9.5 Humane Treatment and Basic Protections for POWs
524
9.6 Security Measures With Respect to POWs
529
9.7 POW Effects and Articles of Personal Use
530
9.8 Interrogation of POWs
532
9.9 Evacuation From Combat Areas
534
9.10 Transit or Screening Facilities
536
9.11 General Conditions in POW Camps: Location, Safety, Hygiene, and Living
Conditions
538
9.12 Segregation of POWs
544
9.13 Food, Water, Tobacco, and Clothing for POWs
545
9.14 Medical Attention for Interned POWs
548
9.15 Religious Exercise by POWs
550
9.16 Intellectual, Physical, and Recreational Activities
551
9.17 Canteens for POWs
553
9.18 Financial Resources of POWs
555
9.19 POW Labor
562
9.20 POW Correspondence and Relief Shipments
569
9.21 Private Legal Matters of POWs
577
9.22 Internal Discipline of POW Camps
578
9.23 POW Requests, Complaints, and Reports About Conditions of Captivity
582
9.24 POW Representatives
584
9.25 POW Escapes
591
9.26 General Principles Applicable to POW Discipline
595
9.27 Disciplinary Proceedings and Punishment
598
9.28 Judicial Proceedings and Punishment
603
9.29 Transfer of POWs From the POW Camp
610
9.30 Transfer of POWs to the Custody of Another Detaining Power
611
9.31 National Accounting of the Detention of POWs
613
9.32 Role of the Protecting Power in the GPW
618
9.33 Access to POWs by the Protecting Powers, ICRC, and Relief Organizations
621
9.34 Death of POWs
622
9.35 Exchanges and Other Release and Repatriation of POWs During Hostilities
626
9.36 Direct Repatriation and Accommodation in Neutral Countries During
Hostilities
627
9.37 Release and Repatriation After Hostilities
632
9.38 Procedure on Release and Repatriation After Hostilities
638
9.39 Code of Conduct for U.S. Armed Forces
640
X - Civilians in the Hands of a Party to the Conflict
644
10.1 Introduction
645
10.2 National-Level GC Implementation Measures
647
10.3 Protected Person Status
648
10.4 Derogation for Security Reasons
654
10.5 Humane Treatment and Other Basic Protections for Protected Persons
655
xi
10.6 Measures of Control and Security
659
10.7 General Treatment of Protected Persons in a Belligerent’s Home Territory
662
10.8 Expulsion From Areas Within a Belligerent’s Home Territory and Departure
and Transfers of Protected Persons From a Belligerent’s Home Territory
664
10.9 Internment
667
10.10 Segregation of Internees
671
10.11 Safety, Hygiene, and Living Conditions in Places of Internment
672
10.12 Canteens for Internees
675
10.13 Food, Water, Tobacco, and Clothing for Internees
677
10.14 Medical Attention for Internees
678
10.15 Religious Exercise by Internees
680
10.16 Intellectual, Physical, and Recreational Activities
682
10.17 Internee Labor
683
10.18 Internees’ Articles of Personal Use
685
10.19 Financial Resources of Internees
686
10.20 Administration of Places of Internment and Discipline
689
10.21 Internee Petitions, Complaints, and Reports About Conditions of
Internment
690
10.22 Internee Committees
692
10.23 Internee Correspondence and Relief Shipments
696
10.24 Private Legal Matters of Internees
703
10.25 Internees and Visits of Family and Friends
705
10.26 Internee Escapes
706
10.27 General Provisions Applicable to Both Judicial and Disciplinary Sanctions
Regarding Internees
707
10.28 Disciplinary Proceedings and Punishment
708
10.29 Judicial Proceedings Regarding Protected Persons in Occupied Territory or
Internees in a Belligerent’s Home Territory
713
10.30 Transfers of Internees From the Place of Internment
717
10.31 National Accounting for Protected Persons in Its Power
720
10.32 Role of the Protecting Power in the GC
725
10.33 Access to Internees by Protecting Powers, ICRC, and Other Relief
Organizations
727
10.34 Death of Internees
729
10.35 Release, Return, Repatriation of Internees After the Close of Hostilities
732
XI - Military Occupation
735
11.1 Introduction
735
11.2 When Military Occupation Law Applies
744
11.3 End of Occupation and Duration of GC Obligations
750
11.4 Legal Position of the Occupying Power
752
11.5 Duty of the Occupying Power to Ensure Public Order and Safety
754
11.6 Protection of the Population of an Occupied Territory
756
11.7 Authority of the Occupying Power Over Inhabitants
758
11.8 Administration of Occupied Territory
761
xii
11.9 Local Law and Legislation
763
11.10 Ordinary Courts in Occupied Territory
767
11.11 Criminal Law in Occupied Territory
769
11.12 Movement of Persons in Occupied Territory
777
11.13 Protection of Children in Occupied Territory
780
11.14 Food and Medical Supplies for the Civilian Population
781
11.15 Public Health and Hygiene
782
11.16 Spiritual Assistance
784
11.17 Relief Efforts and Consignments
785
11.18 Enemy Property During Occupation
788
11.19 Protection of Cultural Property During Occupation
798
11.20 Labor of Protected Persons in Occupied Territory
800
11.21 Judges and Other Public Officials
806
11.22 Public Finances and Taxes
807
11.23 Other Economic Regulation of Occupied Territory
817
XII - Non-Hostile Relations Between Belligerents
822
12.1 Introduction
822
12.2 Principle of Good Faith in Non-Hostile Relations
825
12.3 Methods for Communication Between Belligerents
826
12.4 The White Flag of Truce to Initiate Negotiations
827
12.5 Rules for Parlementaires
829
12.6 Military Passports, Safe-Conducts, and Safeguards
834
12.7 Cartels
839
12.8 Capitulations - Negotiated Instruments of Surrender
839
12.9 Capitulations - Subjects Usually Addressed
843
12.10 Capitulations - Violations and Denunciation
845
12.11 Armistices and Other Cease-Fire Agreements
847
12.12 Armistices - Subjects Usually Addressed
852
12.13 Armistices - Violations and Denunciation
856
12.14 U.N. Security Council Cease-Fires
858
XIII - Naval Warfare
860
13.1 Introduction
860
13.2 Legal Boundaries of the Oceans
862
13.3 Overview of Rules for Naval Engagements
870
13.4 Enemy Warships
873
13.5 Enemy Merchant Vessels
874
13.6 Enemy Vessels Exempt From Capture or Destruction
877
13.7 Submarine Warfare
879
13.8 Belligerent Control of the Immediate Area of Naval Operations
880
13.9 Maritime and Airspace Zones: Exclusion, War, Operational, Warning, and
Safety
882
13.10 Blockade
886
xiii
13.11 Naval Mines
892
13.12 Torpedoes
898
13.13 Deception by Naval Forces, Including the Use of Enemy or Neutral Flags
898
XIV - Air and Space Warfare
900
14.1 Introduction
900
14.2 Legal Boundaries of Airspace
904
14.3 Aircraft Status
909
14.4 Status of Aircrew on Military Aircraft
912
14.5 Measures Short of Attack: Interception, Diversion, and Capture
914
14.6 Belligerent Control of Aviation in the Immediate Vicinity of Hostilities
916
14.7 Airspace Zones
916
14.8 Attacks Against Military Objectives in the Air
917
14.9 Air Attacks Against Military Objectives on the Ground
920
14.10 International Law And Warfare in Outer Space
922
XV - The Law of Neutrality
929
15.1 Introduction
929
15.2 Application of the Law of Neutrality
933
15.3 Overview of the Neutrality Law’s Framework of Reciprocal Rights and
Duties
939
15.4 Remedies for Violations of Neutrality Law
943
15.5 Prohibition on the Use of Neutral Territory as a Base of Operations
946
15.6 Neutral Persons
950
15.7 Neutral Waters
954
15.8 Passage of Belligerent Vessels and Aircraft Through International Straits and
Archipelagic Sea Lanes
957
15.9 Additional Rules Applicable to Neutral Ports, Roadsteads, and Internal
Waters
959
15.10 Neutral Airspace
964
15.11 Belligerent Right of Angary
965
15.12 Neutral Commerce and Carriage of Contraband
967
15.13 Belligerent Right of Visit and Search of Merchant Vessels and Civil
Aircraft
973
15.14 Acquisition of Enemy Character by Neutral-Flagged Merchant Vessels and
Neutral-Marked Civil Aircraft
977
15.15 Capture of Neutral Vessels and Aircraft
979
15.16 Belligerent Forces Taking Refuge in Neutral Territory
984
15.17 POWs or Internees Brought to, or Received by, a Neutral State
989
15.18 Authorized Passage of Wounded and Sick Combatants Through Neutral
Territory
991
XVI - Cyber Operations
994
xiv
16.1 Introduction
994
16.2 Application of the Law of War to Cyber Operations
996
16.3 Cyber Operations and Jus ad Bellum
998
16.4 Cyber Operations and the Law of Neutrality
1002
16.5 Cyber Operations and Jus in Bello
1003
16.6 Legal Review of Weapons That Employ Cyber Capabilities
1008
XVII - Non-International Armed Conflict (NIAC)
1010
17.1 Introduction
1010
17.2 Application of International Law to NIACs
1015
17.3 Special Agreements Between Parties to the Conflict
1023
17.4 A State’s Use of Its Domestic Law and NIAC
1025
17.5 Principle of Distinction in NIAC
1029
17.6 Respect and Humane Treatment of Persons Taking No Active Part in
Hostilities in NIAC
1032
17.7 Rules on Conducting Attacks in NIAC
1033
17.8 Impartial Humanitarian Organizations and Humanitarian Activities During
NIAC
1035
17.9 Protection of the Civilian Population in NIAC
1035
17.10 Protection of Children in NIAC
1037
17.11 Protection of Cultural Property in NIAC
1038
17.12 Use of Captured or Surrendered Enemy Personnel in NIAC
1039
17.13 Weapons in NIAC
1041
17.14 Protection of the Wounded, Sick, Shipwrecked, and Dead in NIAC
1042
17.15 Protection of Medical and Religious Personnel and Medical Transports in
NIAC
1044
17.16 Display of the Distinctive Emblem in NIAC
1045
17.17 Detention in NIAC
1046
17.18 Non-Intervention and Neutral Duties in NIAC
1047
XVIII - Implementation and Enforcement of the Law of War
1052
18.1 Introduction
1052
18.2 Prudential Reasons Supporting the Implementation and Enforcement of the
Law of War
1055
18.3 Duties of Individual Members of the Armed Forces
1057
18.4 Commanders’ Duty to Implement and Enforce the Law of War
1059
18.5 Role of Judge Advocates and Legal Advisers
1061
18.6 Dissemination, Study, and Other Measures to Facilitate Understanding of
Duties Under the Law of War
1063
18.7 Instructions, Regulations, and Procedures to Implement and Enforce the Law
of War
1066
18.8 Considering Law of War Obligations in the Planning of Military Operations
1069
18.9 States’ Obligations With Respect to Violations of the Law of War
1070
18.10 Methods for Responding to Violations of the Law of War by the Enemy
1077
xv
18.11 Protests and Demands to the Offending Party
1078
18.12 U.N. Security Council and Enforcement of the Law of War
1078
18.13 National Investigations of Alleged Violations of the Law of War
1082
18.14 International Mechanisms to Investigate Alleged Law of War Violations
1084
18.15 Protecting Power and Other Neutral Intermediaries
1085
18.16 Compensation for Violations of the Law of War
1089
18.17 Retorsion
1092
18.18 Reprisals
1093
18.19 Discipline in National Jurisdictions of Individuals for Violations of the Law
of War
1100
18.20 Prosecution in International and Hybrid Courts
1108
18.21 Limits on the Punishment of Individuals Under the Law of War
1113
18.22 Principles of Individual Criminal Responsibility for Crimes Under
International Law
1118
18.23 Theories of Individual Criminal Liability
1122
XIX Documentary Appendix - Notes on Treaties and Other Relevant Documents
1131
19.1 Introduction
1131
19.2 Lists of Treaties and Other Documents
1131
19.3 Lieber Code
1138
19.4 1856 Paris Declaration Respecting Maritime Law
1139
19.5 1864 GWS
1140
19.6 1868 St. Petersburg Declaration
1140
19.7 1899 and 1907 Hague Declarations on Weapons
1141
19.8 1899 Hague II and 1907 Hague IV Conventions and Annexed Regulations
Regarding Land Warfare
1143
19.9 1907 Hague X
1146
19.10 1922 Washington Treaty on Submarines and Noxious Gases
1146
19.11 1923 Hague Air and Radio Rules
1147
19.12 1925 Geneva Gas and Bacteriological Protocol
1148
19.13 1929 Geneva Conventions
1150
19.14 1930 London Treaty for the Limitation and Reduction of Naval Armament
and 1936 London Protocol
1151
19.15 1935 Roerich Pact
1151
19.16 1949 Geneva Conventions
1152
19.17 1954 Hague Cultural Property Convention
1157
19.18 Vienna Convention on the Law of Treaties
1159
19.19 Biological Weapons Convention
1159
19.20 1977 Additional Protocols to the 1949 Geneva Conventions
1160
19.21 CCW, CCW Amended Article 1, and CCW Protocols
1164
19.22 Chemical Weapons Convention
1172
19.23 Rome Statute of the International Criminal Court
1174
19.24 1999 U.N. Secretary General’s Bulletin for U.N. Forces
1175
19.25 2005 ICRC Study on Customary International Humanitarian Law
1175
19.26 AP III
1176
xvi
LIST OF ABBREVIATIONS
To make the manual easier to read, the use of abbreviations has often been avoided,
especially in the main text. Nonetheless, the following abbreviations of the titles of documents
have been used for frequently cited documents.
Abbreviation
Long Form
1899 Hague II
Convention with Respect to the Laws and Customs of War
on Land, Jul. 29, 1899, 32 Stat. 1803
1899 Hague II Reg.
Regulations Respecting the Laws and Customs of War on
Land, annexed to Convention with Respect to the Laws and
Customs of War on Land, Jul. 29, 1899, 32 Stat. 1803,
1811
1909 Declaration of London
Declaration Concerning the Laws of Maritime War, Feb.
26, 1909, reprinted in James Brown Scott, The Declaration
of London, February 26, 1909: A Collection of Official
Papers and Documents Relating to the International Naval
Conference Held in London, December, 1908—February,
1909 (1919)
1914 Rules of Land Warfare
War Department, Office of the Chief of Staff, Rules of
Land Warfare (Apr. 25, 1914)
1925 Geneva Gas and
Protocol for the Prohibition of the Use in War of
Bacteriological Protocol
Asphyxiating, Poisonous, or Other Gases, and of
Bacteriological Methods of Warfare, Jun. 17, 1925, 94
LNTS 65
1928 Pan American Maritime
Pan American Maritime Neutrality Convention, Feb. 20,
Neutrality Convention
1928, 47 Stat. 1989
1929 GPW
Geneva Convention Relative to the Treatment of Prisoners
of War, Jul. 27, 1929, 47 Stat. 2021
1929 GWS
Geneva Convention for the Amelioration of the Condition
of the Wounded and Sick of Armies in the Field, Jul. 27,
1929, 47 Stat. 2074
1940 Rules of Land Warfare
War Department, Field Manual 27-10, Rules of Land
Warfare (1940)
1944 Chicago Convention
Convention on International Civil Aviation, Dec. 7, 1944,
61 Stat. 1180
1954 Hague Cultural Property
Convention for the Protection of Cultural Property in the
Convention
Event of Armed Conflict, 249 UNTS 240
1955 NWIP 10-2
Department of the Navy, Office of the Chief of Naval
Operations, Naval Warfare Information Publication 10-2,
Law of Naval Warfare (Sept. 1955), reprinted as Appendix
in Robert W. Tucker, The Law of War and Neutrality at
Sea (U.S. Naval War College International Law Studies,
Volume 50, 1955)
1956 FM 27-10 (Change No. 1
Department of the Army Field Manual 27-10, The Law of
1976)
Land Warfare (Jul. 18, 1956 with Change 1, Jul. 15, 1976)
xvii
Abbreviation
Long Form
1958 UK Manual
United Kingdom War Office, Manual of Military Law, Part
III: The Law of War on Land (1958)
1976 Air Force Pamphlet 110-31
Department of the Air Force Pamphlet 110-31,
International Law - The Conduct of Armed Conflict and
Air Operations (Nov. 19, 1976)
1989 NWP 9
Department of the Navy, Office of the Judge Advocate
General, Annotated Supplement to the Commander’s
Handbook on the Law of Naval Operations, NWP
(Rev.A)/FMFM 1-10 (1989)
1997 Multi-Service Detention
Army Regulation 190-8 / Office of the Chief of Naval
Regulation
Operations Instruction 3461.6 / Air Force Joint Instruction
31-304 / Marine Corps Order 3461.1, Enemy Prisoners of
War, Retained Personnel, Civilian Internees and Other
Detainees (Oct. 1, 1997)
1997 NWP 9
U.S. Naval War College, Center for Naval Warfare Studies,
Oceans Law and Policy Department, Annotated Supplement
to the Commander’s Handbook on the Law of Naval
Operations (1997)
2001 Canadian Manual
Canada, Department of National Defence, Joint Doctrine
Manual B-GJ-005-104/FP-021, Law of Armed Conflict at
the Operational and Tactical Levels (Aug. 13, 2001)
2004 UK Manual
United Kingdom Ministry of Defence, Joint Service
Publication 383, The Joint Service Manual of the Law of
Armed Conflict (2004)
2006 Australian Manual
Australian Defence Force, Australian Defence Doctrine
Publication 06.4, Law of Armed Conflict (May 11, 2006)
2007 NWP 1-14M
Department of the Navy, Naval Warfare Publication 1-14M
/ Marine Corps Warfighting Publication 5-12.1 /
Commandant Publication P5800.7A, The Commander’s
Handbook on the Law of Naval Operations (Jul. 2007)
2013 German Manual
Germany, Federal Ministry of Defence, Joint Service
Regulation (ZDv) 15/2, Law of Armed Conflict Manual
(May 1, 2013)
AJIL
American Journal of International Law
AP I
Protocol (I) Additional to the Geneva Conventions of
August 12, 1949, and Relating to the Protection of Victims
of International Armed Conflicts, Jun. 8, 1977, 1125 UNTS
3
AP II
Protocol (II) Additional to the Geneva Conventions of 12
August 1949, and Relating to the Protection of Victims of
Non-International Armed Conflicts, Jun. 8, 1977, 1125
UNTS 609
xviii
Abbreviation
Long Form
AP III
Protocol (III) Additional to the Geneva Conventions of 12
August 1949, and Relating to the Adoption of an
Additional Distinctive Emblem, Dec. 8, 2005, 2404 UNTS
1
Appendix to 1985 CJCS Memo on
Appendix to John W. Vessey, Jr., Chairman, Joint Chiefs of
AP I
Staff, Review of the 1977 First Additional Protocol to the
Geneva Conventions of 1949, May 3, 1985.
Bevans
Charles I. Bevans, Assistant Legal Adviser, Department of
State, Treaties and Other International Agreements of the
United States of America, 1776-1949 (13 Volumes, 1968-
1976)
Biological Weapons Convention
Convention on the Prohibition of the Development,
Production and Stockpiling of Bacteriological (Biological)
and Toxin Weapons and on Their Destruction, Apr. 10,
1972, 1015 UNTS 163
Bothe, Partsch, & Solf, New Rules
Michael Bothe, Karl Josef Partsch, & Waldemar A. Solf,
New Rules for Victims of Armed Conflicts (1982)
CCW
Convention on Prohibitions or Restrictions on the Use of
Certain Conventional Weapons Which May be Deemed to
be Excessively Injurious or to Have Indiscriminate Effects,
Oct. 10, 1980, 1342 UNTS 137
CCW Amended
Amendment to Article I of the Convention on Prohibitions
or Restrictions on the Use of Certain Conventional
Weapons Which May be Deemed to be Excessively
Injurious or to Have Indiscriminate Effects, Dec. 21, 2001,
2260 UNTS 82
CCW Amended Mines Protocol
Protocol (II) on Prohibitions or Restrictions on the Use of
Mines, Booby-Traps and Other Devices, as Amended on
May 3, 1996, Annexed to the Convention on Prohibitions
or Restrictions on the Use of Certain Conventional
Weapons Which May be Deemed to be Excessively
Injurious or to Have Indiscriminate Effects, May 3, 1996,
2048 UNTS 93
CCW Protocol I
Protocol (I) on Non-Detectable Fragments, Annexed to the
Convention on Prohibitions or Restrictions on the Use of
Certain Conventional Weapons Which May be Deemed to
be Excessively Injurious or to Have Indiscriminate Effects,
Oct. 10, 1980, 1342 UNTS 137
CCW Protocol III on Incendiary
Protocol (III) on Prohibitions or Restrictions on the Use of
Weapons
Incendiary Weapons, Annexed to the Convention on
Prohibitions or Restrictions on the Use of Certain
Conventional Weapons Which May be Deemed to be
Excessively Injurious or to Have Indiscriminate Effects,
Oct. 10, 1980, 1342 UNTS 137
xix
Abbreviation
Long Form
CCW Protocol IV on Blinding
Protocol (IV) on Blinding Laser Weapons, Annexed to the
Laser Weapons
Convention on Prohibitions or Restrictions on the Use of
Certain Conventional Weapons Which May be Deemed to
be Excessively Injurious or to Have Indiscriminate Effects,
Oct. 13, 1995, 1380 UNTS 163
CCW Protocol V on Explosive
Protocol (V) on Explosive Remnants of War, Annexed to
Remnants of War
the Convention on Prohibitions or Restrictions on the Use
of Certain Conventional Weapons Which May be Deemed
to be Excessively Injurious or to Have Indiscriminate
Effects, Nov. 28, 2003, 2399 UNTS 100
Chairman’s Commentary to the
The Copenhagen Process on the Handling of Detainees in
Copenhagen Process: Principles
International Military Operations, Chairman’s Commentary
and Guidelines
to the Copenhagen Process: Principles and Guidelines
(Denmark, Ministry of Foreign Affairs, Oct. 19, 2012)
Chemical Weapons Convention
Convention on the Prohibition of the Development,
Production, Stockpiling and Use of Chemical Weapons and
on Their Destruction, Jan. 13, 1993, 1974 UNTS 317
Copenhagen Process: Principles
The Copenhagen Process on the Handling of Detainees in
and Guidelines
International Military Operations, The Copenhagen
Process: Principles and Guidelines (Denmark, Ministry of
Foreign Affairs, Oct. 19, 2012)
Digest of United States Practice in
Digest of United States Practice in International Law
International Law
(Department of State, Office of the Legal Adviser)
ENMOD Convention
Convention on the Prohibition of Military or Any Other
Hostile Use of Environmental Modification Techniques,
Dec. 10, 1976, 1108 UNTS 151
Final Record of 1949 Geneva
Diplomatic Conference of Geneva, Final Record of the
Diplomatic Conference
Diplomatic Conference of Geneva of 1949 (Switzerland,
Federal Political Department, 1949)
Final Report on the Persian Gulf
Department of Defense, Conduct of the Persian Gulf War:
War
Final Report to Congress (1992)
GC
Geneva Convention Relative to the Protection of Civilian
Persons in Time of War, Aug. 12, 1949, 75 UNTS 287
GC Commentary
Jean S. Pictet, Geneva Convention Relative to the
Protection of Civilian Persons in Time of War:
Commentary (International Committee of the Red Cross,
1958)
GPW
Geneva Convention Relative to the Treatment of Prisoners
of War, Aug. 12, 1949, 75 UNTS 135
GPW Commentary
Jean S. Pictet, Geneva Convention Relative to the
Treatment of Prisoners of War: Commentary (International
Committee of the Red Cross, 1960)
Greenspan, Modern Law of Land
Morris Greenspan, The Modern Law of Land Warfare
Warfare
(1959)
xx
Abbreviation
Long Form
Grotius, Law of War & Peace
Hugo Grotius, The Law of War and Peace: De Jure Belli
ac Pacis Libri Tres (translated by Francis W. Kelsey, 1925)
GWS
Geneva Convention for the Amelioration of the Condition
of the Wounded and Sick in Armed Forces in the Field,
Aug. 12, 1949, 75 UNTS 31
GWS Commentary
Jean S. Pictet, Geneva Convention for the Amelioration of
the Condition of the Wounded and Sick in Armed Forces in
the Field: Commentary (International Committee of the
Red Cross, 1952)
GWS-Sea
Geneva Convention for the Amelioration of the Condition
of the Wounded, Sick and Shipwrecked Members of Armed
Forces at Sea, Aug. 12, 1949, 75 UNTS 85
GWS-Sea Commentary
Jean S. Pictet, Geneva Convention for the Amelioration of
the Condition of the Wounded, Sick and Shipwrecked
Members of Armed Forces at Sea: Commentary
(International Committee of the Red Cross, 1960)
Hague IV
Convention (IV) Respecting the Laws and Customs of War
on Land, Oct. 18, 1907, 36 Stat. 2277
Hague IV Reg.
Regulations Respecting the Laws and Customs of War on
Land, Annex to Convention (IV) Respecting the Laws and
Customs of War on Land, Oct. 18, 1907, 36 Stat. 2295
Hague IX
Convention (IX) Concerning Bombardment by Naval
Forces in Time of War, Oct. 18, 1907, 36 Stat. 2351
Hague V
Convention (V) Respecting the Rights and Duties of
Neutral Powers and Persons in Case of War on Land, Oct.
18, 1907, 36 Stat. 2310
Hague VIII
Convention (VIII) Relative to the Laying of Automatic
Submarine Contact Mines, Oct. 18, 1907, 36 Stat. 2332
Hague X
Convention (X) for the Adaptation to Maritime Warfare of
the Principles of the Geneva Convention, Oct. 18, 1907, 36
Stat. 2371
Hague XI
Convention (XI) Relative to Certain Restrictions with
Regard to the Exercise of the Right of Capture in Naval
War, Oct. 18, 1907, 36 Stat. 2396
Hague XIII
Convention (XIII) Concerning the Rights and Duties of
Neutral Powers in Naval War, Oct. 18, 1907, 36 Stat. 2415
ICJ Statute
Statute of the International Court of Justice (Annex to the
Charter of the United Nations), Jun. 26, 1945, 59 Stat. 1055
ICRC AP Commentary
Jean S. Pictet et al., Commentary on the Additional
Protocols of 8 June 1977 to the Geneva Conventions of 12
August 1949 (International Committee of the Red Cross,
1987)
xxi
Abbreviation
Long Form
ICTR
International Criminal Tribunal for the Prosecution of
Persons Responsible for Genocide and Other Serious
Violations of International Humanitarian Law Committed
in the Territory of Rwanda and Rwandan Citizens
Responsible for Genocide and Other Such Violations
Committed in the Territory of Neighbouring States,
between 1 January 1994 and 31 December 1994
ICTR Statute
Statute of the ICTR, Annex to U.N. Security Council
Resolution 955 (1994), U.N. Doc. S/RES/955(1994) (Nov.
8, 1994).
ICTY
International Tribunal for the Prosecution of Persons
Responsible for Serious Violations of International
Humanitarian Law Committed in the Territory of the
Former Yugoslavia since 1991
ICTY Statute
Statute of the ICTY, Annex to Report of the Secretary-
General Pursuant to Paragraph 2 of Security Council
Resolution 808 (1993), U.N. Doc. S/25704 (May 3, 1993),
adopted by U.N. Security Council Resolution 827 (1993),
U.N. Doc. S/RES/827(1993) (May 25, 1993).
J.A.G.S. Text No. 11, Law of
U.S. Army, The Judge Advocate General’s School Text
Belligerent Occupation
No. 11, Law of Belligerent Occupation (Jun. 1, 1944,
reissued Jul. 2, 1945)
Lauterpacht, II Oppenheim’s
Lassa Oppenheim, International Law, Volume II: Disputes,
International Law
War and Neutrality (edited by H. Lauterpacht, 7th ed.,
1952)
Levie, Documents on POWs
Howard S. Levie, Documents on Prisoners of War (U.S.
Naval War College International Law Studies, Volume 60,
1979)
Levie, POWs
Howard Levie, Prisoners of War in International Armed
Conflicts (U.S. Naval War College International Law
Studies, Volume 59, 1978)
Lieber Code
E. D. Townsend, Assistant Adjutant General, General
Orders No. 100, Instructions for the Government of Armies
of the United States in the Field, Apr. 24, 1863, reprinted in
Instructions for the Government of Armies of the United
States in the Field (Government Printing Office, 1898).
LNTS
League of Nations Treaty Series
LOS Convention
United Nations Convention on the Law of the Sea, Dec.10,
1982, 1833 UNTS 396.
Message from the President
Message from the President of the United States
Transmitting AP II
Transmitting the Protocol II Additional to the Geneva
Conventions of August 12, 1949, and Relating to the
Protection of Victims of Noninternational Armed Conflicts,
Concluded at Geneva on June 10, 1977, Treaty Doc. 100-2
(1987)
xxii
Abbreviation
Long Form
Message from the President
Message from the President of the United States
Transmitting AP III, CCW
transmitting Protocol Additional to the Geneva
Amended Article 1, and CCW
Conventions of 12 August 1949, and Relating to the
Protocol V on Explosive
Adoption of an Additional Distinctive Emblem (The
Remnants of War
“Geneva Protocol III”), Adopted at Geneva on December 8,
2005, and Signed by the United States on that date; The
Amendment to Article 1 of the Convention on Prohibitions
or Restrictions on the Use of Certain Conventional
Weapons Which May Be Deemed to be Excessively
Injurious or to Have Indiscriminate Effects (“The CCW
Amendment”); and The CCW Protocol Explosive
Remnants of War (The “CCW Protocol V”), Treaty Doc.
109-10 (2006)
Message from the President
Message from the President of the United States
Transmitting LOS Convention
transmitting the United Nations Convention on the Law of
the Sea, with Annexes, and the Agreement Relating to the
Implementation of Part XI of the United Nations
Convention on the Law of the Sea, with Annex, Adopted at
New York on July 28, 1994 and signed by the United
States, Subject to Ratification on July 29, 1994, Treaty
Doc. 103-09 (1994)
Message from the President
Message From the President of the United States
Transmitting the 1925 Geneva Gas
Transmitting The Protocol for the Prohibition of the Use in
and Bacteriological Protocol
War of Asphyxiating, Poisonous, or Other Gases, and of
Bacteriological Methods of Warfare, Signed at Geneva
June 17, 1925, Executive J (1970)
Message from the President
Message from the President of the United States
Transmitting the 1954 Hague
Transmitting the Hague Convention for the Protection of
Cultural Property Convention
Cultural Property in the Event of Armed Conflict (the
Convention) and, for Accession, the Hague Protocol,
Concluded on May 14, 1954, and Entered into Force on
August 7, 1956 with Accompanying Report from the
Department of State on the Convention and the Hague
Protocol, Treaty Doc. 106-1 (1999)
xxiii
Abbreviation
Long Form
Message from the President
Message From the President of the United States
Transmitting the CCW Amended
Transmitting Protocols to the 1980 Convention on
Mines Protocol, Protocol III on
Prohibitions or Restrictions on the use of Certain
Incendiary Weapons, and Protocol
Conventional Weapons which may be deemed to be
IV on Blinding Laser Weapons
excessively injurious or to Have Indiscriminate effects:
The Amended Protocol on Prohibitions or Restrictions on
the Use of Mines, Booby-traps or other devices (Protocol II
or the Amended Mines Protocol); The Protocol On
Prohibitions or Restrictions on the Use of Incendiary
Weapons (Protocol III or the Incendiary Weapons
Protocol); and the Protocol on Blinding Laser Weapons
(Protocol IV), Treaty Doc. 105-1 (1997)
Message from the President
Message from the President of the United States
Transmitting the Chemical
Transmitting the Convention on the Prohibition of
Weapons Convention
Development, Production, Stockpiling, and use of
Chemical Weapons and on their Destruction, Opened for
Signature and Signed by the United States at Paris on Jan.
13, 1993, Treaty Doc. 103-21 (1993)
Message from the President
Message from the President of the United States
Transmitting the VCLT
Transmitting the Vienna Convention on the Law of Treaties
Signed for the United States on April 24, 1970, Executive L
(1971)
Moore’s Digest
John Bassett Moore, A Digest of International Law (8
Volumes, 1906)
Official Records of the CDDH
Official Records of the Diplomatic Conference on the
Reaffirmation and Development of International
Humanitarian Law Applicable in Armed Conflicts, Geneva
1974-1977 (16 Volumes, 1978)
Outer Space Treaty
Treaty on Principles Governing the Activities of States in
the Exploration and Use of Outer Space, Including the
Moon and Other Celestial Bodies, Jan. 27, 1967, 610
UNTS 205
Public Papers of the Presidents
Public Papers of the Presidents of the United States
(National Archives and Records Administration, Office of
the Federal Register)
Regulations for the Execution of
Regulations for the Execution of the Convention for the
the 1954 Hague Cultural Property
Protection of Cultural Property in the Event of Armed
Convention
Conflict, Annexed to the Hague Cultural Property
Convention, May 14, 1954, 249 UNTS 270
Roerich Pact
Treaty between the United States of America and other
American Republics on the Protection of Artistic and
Scientific Institutions and Historic Monuments, Apr. 15,
1935, 49 Stat. 3267
Rome Statute
Rome Statute of the International Criminal Court, July 17,
1998, 2187 UNTS 90
xxiv
Abbreviation
Long Form
Spaight, Air Power and War
James Maloney Spaight, Air Power and War Rights (3rd
Rights
ed., 1947)
Spaight, War Rights on Land
James Maloney Spaight, War Rights on Land (1911)
Stat.
United States Statutes at Large
Technical Annex to CCW
Technical Annex to Protocol (II) on Prohibitions or
Amended Mines Protocol
Restrictions on the Use of Mines, Booby-Traps and Other
Devices, as Amended on May 3, 1996, Annexed to the
Convention on Prohibitions or Restrictions on the Use of
Certain Conventional Weapons Which May be Deemed to
be Excessively Injurious or to Have Indiscriminate Effects,
May 3, 1996, 2048 UNTS 144
Technical Annex to CCW Protocol
Technical Annex to Protocol (V) on Explosive Remnants of
V On Explosive Remnants of War
War, Annexed to the Convention on Prohibitions or
Restrictions on the Use of Certain Conventional Weapons
Which May be Deemed to be Excessively Injurious or to
Have Indiscriminate Effects, Nov. 28, 2003, 2399 UNTS
132
Trial of the Major War Criminals
Trial of the Major War Criminals Before the International
Before the IMT
Military Tribunal (42 Volumes, 1947-1949)
Trials of War Criminals Before the
Trials of War Criminals Before the Nuernberg Military
NMT
Tribunals Under Control Council Law No. 10 (15 Volumes,
1949-1953)
Tucker, The Law of War and
Robert W. Tucker, The Law of War and Neutrality at Sea
Neutrality at Sea
(U.S. Naval War College International Law Studies,
Volume 50, 1955)
U.N. Charter
Charter of the United Nations, Jun. 26, 1945, 59 Stat. 1031
U.N. Law Reports
United Nations War Crimes Commission, Law Reports of
the Trials of War Criminals (15 Volumes 1947-1949)
U.S. Response to ICRC CIHL
John B. Bellinger, III, Legal Adviser, Department of State,
Study
& William J. Haynes II, General Counsel, Department of
Defense, Letter to Dr. Jacob Kellenberger, President,
International Committee of the Red Cross, Regarding
Customary International Humanitarian Law Study, Nov. 3,
2006, reprinted in 46 International Legal Materials 514
(2007).
U.S.C.
United States Code (as of the date of publication of this
manual)
UNTS
United Nations Treaty Series
Vattel, The Law of Nations
Emer de Vattel, The Law of Nations, or the Principles of
the Law of Nature, Applied to the Conduct and Affairs of
Nations and Sovereigns (translated by Charles Fenwick,
1916)
VCLT
Vienna Convention on the Law of Treaties, May 23, 1969,
1155 UNTS 331
xxv
Abbreviation
Long Form
Von Glahn, The Occupation of
Gerhard von Glahn, The Occupation of Enemy Territory
Enemy Territory
(1957)
Whiteman’s Digest
Marjorie M. Whiteman, Assistant Legal Adviser,
Department of State, Digest of International Law (15
Volumes, 1963-1973)
Winthrop, Military Law &
William Winthrop, Military Law and Precedents (2nd. ed.,
Precedents
1920)
xxvi
I - General Background
Chapter Contents
1.1 Purpose and Scope of This Manual
1.2 Use of Footnotes, Sources, Cross-References, and Signals in This Manual
1.3 Definition of the Law of War
1.4 Object and Nature of War
1.5 “War” as a Legal Concept
1.6 Law of War Distinguished From Certain Topics
1.7 Treaties
1.8 Customary International Law
1.9 Subsidiary Means of Determining International Law
1.10 Legal Force of the Law of War
1.11 Jus ad Bellum
1.1 PURPOSE AND SCOPE OF THIS MANUAL
1.1.1 Purpose. The purpose of this manual is to provide information on the law of war to
DoD personnel responsible for implementing the law of war and executing military operations.1
This manual represents the legal views of the Department of Defense. This manual does
not, however, preclude the Department from subsequently changing its interpretation of the law.
Although the preparation of this manual has benefited from the participation of lawyers from the
Department of State and the Department of Justice, this manual does not necessarily reflect the
views of any other department or agency of the U.S. Government or the views of the U.S.
Government as a whole.
This manual is not intended to, and does not, create any right or benefit, substantive or
procedural, enforceable at law or in equity against the United States, its departments, agencies, or
other entities, its officers or employees, or any other person.
1.1.2 Scope. This manual is not a definitive explanation of all law of war issues. This
manual focuses on jus in bello - law relating to the conduct of hostilities and the protection of
war victims.
This manual seeks to address the law of war that is applicable to the United States,
including treaties to which the United States is a Party, and applicable customary international
law. It provides legal rules, principles, and discussion, particularly with respect to DoD practice.
Although the views of other States may be referenced in this manual, it is not a purpose of this
manual to describe the views of other States, which may differ from views expressed in this
manual.
1 Refer to § 1.3 (Definition of the Law of War).
1
This manual is not a substitute for the careful practice of law. As specific legal issues
arise, legal advisers should consider relevant legal and policy materials (e.g., treaty provisions,
judicial decisions, past U.S. practice, regulations, and doctrine), and should apply the law to the
specific factual circumstances.
This manual is intended to be a description of the law as of the date of the manual’s
promulgation. In this vein, much of this manual has been written in the past tense to help ensure
that the text remains accurate, even after subsequent developments have occurred. Every effort
has been made to ensure the accuracy of the manual, but it must be read in the light of later
developments in the law.
1.2 USE OF FOOTNOTES, SOURCES, CROSS-REFERENCES, AND SIGNALS IN THIS MANUAL
1.2.1 Use of Footnotes in This Manual. This manual uses footnotes to provide sources or
cross-references to other sections of the manual in order to clarify, elaborate on, or support the
main text.
An effort has been made to avoid introducing discussion in the footnotes that addresses
different propositions than those discussed in the main text. Although providing tangential
information in footnotes is common in academic legal writing, this practice has been avoided to
the extent possible for principally two reasons. First, it was desirable that this manual’s main
text convey as much information as possible without the reader needing to read the footnotes.
For example, it was desirable to avoid the possibility that a reader might misunderstand a legal
rule addressed in the main text because a notable exception to that rule was addressed only in a
footnote accompanying the text. Second, tangential discussion on a given issue in footnotes
would have made it much more difficult to keep the manual’s treatment of that issue consistent
from section to section and to allow the reader to find all the relevant information about a single
topic. Thus, tangential discussion in footnotes has been avoided, to the extent possible, in favor
of cross-references to the appropriate section of the manual that addresses that topic in more
detail.
1.2.2 Use of Sources in This Manual. This manual cites sources in the footnotes to
support or elaborate upon propositions in the main text. These sources are cited in the footnotes
to help practitioners research particular topics discussed in the main text. Reviewing the cited
sources in their entirety may provide additional contextual information, especially where sources
are only partially quoted in the footnotes.
1.2.2.1 Selection of Sources. The sources cited in the footnotes have been chosen
for a variety of reasons. For example, a source may contain a particularly helpful explanation or
illustration. A source may have been chosen to illustrate U.S. practice or legal interpretation. A
source may have been selected because its author was a particularly influential and respected
international lawyer. For example, the 1956 Department of Army Field Manual 27-10, The Law
of Land Warfare, has been a source of legal guidance for the U.S. armed forces for more than 50
years, and was published in connection with the U.S. ratification of the 1949 Geneva
Conventions. One of the persons who helped prepare the 1956 manual was Richard Baxter, a
highly respected DoD lawyer, who later became a judge on the International Court of Justice.
2
Citation to a particular source should not be interpreted to mean that the cited source
represents an official DoD position, or to be an endorsement of the source in its entirety. For
example, parts of a source, such as an opinion by the International Court of Justice or a
commentary published by the International Committee of the Red Cross, may reflect the DoD
legal interpretation, while other parts of the source may not. Similarly, the citation of the
jurisprudence of the Inter-American Commission on Human Rights should not be understood to
indicate that the United States has accepted the competence of the Inter-American Commission
on Human Rights to apply the law of war.2
1.2.2.2 Use of Older Sources. Older sources are sometimes cited: (1) because
that source is particularly influential; (2) to demonstrate the origin of a legal proposition; or (3)
to illustrate that a particular rule or formulation has a long history.
The citation of an older source should not necessarily be interpreted as an endorsement
that every aspect of that source remains current law. For example, the Lieber Code is a
canonical law of war document for the United States, but parts of it no longer reflect current
law.3 Moreover, an older document produced by a State does not necessarily reflect its current
legal views. For example, the 1958 UK Manual, although a particularly influential law of war
manual prepared by distinguished experts Hersch Lauterpacht and Gerald Draper, has been
superseded by subsequent UK Manuals, which reflect more recent developments in the law for
the United Kingdom (e.g., its ratification of AP I).
1.2.2.3 Quotes Provided From Sources. Quotes from sources are sometimes
given in parentheticals within footnotes. These parentheticals are provided to help practitioners,
such as by facilitating comparison between the main text of the manual and the language used in
the sources. Every effort has been made to quote sources accurately. Practitioners, however,
should verify quotations using the original source.
Certain formatting rules have been followed for quoted material. Two spaces have been
placed after each period ending a sentence. Footnote numbers and carriage returns have been
omitted from quoted text. Otherwise, quotes have not been changed unless noted through the use
of ellipses, brackets, or parentheticals after the quotes indicating the changes made.
1.2.2.4 Citation of Policies and Regulations. Policies and regulations of the U.S.
Government or particular DoD components are sometimes cited as examples of past practice.
This manual, however, seeks primarily to address the law and not to address applicable
U.S. Government or DoD policies or regulations. Many policies and regulations are not
addressed in this manual, and the discussion of some policies, where relevant, should not be
understood to indicate that other pertinent policies or regulations do not exist. Moreover,
2 See, e.g., U.S. Additional Response to the Request for Precautionary Measures—Detention of Enemy Combatants
at Guantanamo Bay, Cuba, Inter-American Commission on Human Rights, Jul. 15, 2002, 2002 DIGEST OF UNITED
STATES PRACTICE IN INTERNATIONAL LAW 1008, 1009 (“Put simply, the Commission’s jurisdiction does not include
the application of the law of armed conflict, the lex specialis governing the status and treatment of persons detained
during armed conflict.”).
3 Refer to § 19.3 (Lieber Code).
3
policies and regulations are constantly updated, so practitioners are advised to ascertain whether
more recent versions of cited policies and regulations have been issued.
In some cases, cancelled issuances or superseded policies or regulations are cited to show
the past practice, and, at times, a series of issuances are cited to illustrate a continuity in practice.
Policies and regulations often exceed the requirements of applicable law, and the mere
citation of a policy or regulation in this manual should not be understood to reflect the view that
the policy or regulation’s requirements have been promulgated out of a sense of legal obligation
for the purposes of assessing customary international law or otherwise intending to reflect legal
requirements.
1.2.2.5 Citation Forms. An effort has been made to make citations forms
consistent throughout the manual, and to provide enough information about each cited source to
reflect its significance and to enable readers to find it.4 This manual has not strictly adhered to
an established system of citation. Although certain citation systems were consulted,
modifications were made as deemed appropriate for this type of resource, to make the citation
forms straightforward and simple and relatively easy for readers to understand. In regard to
abbreviations, for example, this manual generally does not abbreviate the names of academic
journals. Moreover, it is hoped that the quotations from the cited sources that have been
included in footnotes will help readers find the cited sources electronically.
1.2.3 Use of Cross-References in This Manual. This manual uses cross-references in the
footnotes to point the reader to other sections of the manual containing relevant discussion of a
particular topic. In particular, an effort has been made to use cross-references rather than to
repeat discussion of a recurring issue or duplicate citation of legal sources. In sections in which
a law of war rule is only mentioned tangentially or as an example, a cross-reference is used to
direct the reader to the section of the manual in which a more in-depth discussion of that rule and
supporting sources are provided.5
Cross-references are linked to enable the reader to access the referenced section quickly.
4 Cf. Richard A. Posner, The Bluebook Blues (reviewing Harvard Law Review Association, The Bluebook: A
Uniform System of Citation (19th ed., 2010)), THE YALE LAW JOURNAL 850, 852 (2011) (“A system of citation
forms has basically two functions: to provide enough information about a reference to give the reader a general idea
of its significance and whether it’s worth looking up, and to enable the reader to find the reference if he decides that
he does want to look it up. In Goodbye to the Bluebook I suggested four principles to guide the design of such a
system: ‘to spare the writer or editor from having to think about citation form,’ ‘to economize on space and the
reader's time,’ ‘to provide information to the reader,’ and ‘to minimize distraction.’”).
5 Refer to § 1.2.1 (Use of Footnotes in This Manual).
4
1.2.4 Use of Signals in This Manual. This manual uses signals to introduce the sources
and cross-references in the footnotes. The table below identifies the signals used in this manual,
describes their function, and provides examples of their use.
Signal
Function and Examples of Use
[no
Directly states the proposition
signal]
If a person joins a levée en masse, he or she may be held as a POW even if he or she
actually took no part in fighting.1
1 1958 UK MANUAL ¶100 (“If it is shown that they joined the levée en masse, but took
no part in the defence, they may be held as prisoners of war.”).
Identifies the source of a quotation
As the Supreme Court has explained: “Lawful combatants are subject to capture and
detention as prisoners of war by opposing military forces.”2
2 Ex parte Quirin, 317 U.S. 1, 31 (1942).
Identifies an authority referred to in the text
There are additional provisions of the CCW Amended Mines Protocol addressing
international exchanges of information and cooperation in this respect.3
3 CCW AMENDED MINES PROTOCOL art. 11.
See
Clearly supports the proposition but does not directly state it
In addition, observers on military reconnaissance aircraft have not been regarded as
acting clandestinely or under false pretenses.4
4 See HAGUE IV REG. art. 29 (“Persons sent in balloons for the purpose of carrying
despatches and, generally, of maintaining communications between the different parts of
an army or a territory” are not considered spies.).
See also
Elaborates on the proposition
This means that a combatant’s “killing, wounding, or other warlike acts are not
individual crimes or offenses.”5
5 LIEBER CODE art. 57. See also WINTHROP, MILITARY LAW & PRECEDENTS 778 (“The
State is represented in active war by its contending army, and the laws of war justify the
killing or disabling of members of the one army by those of the other in battle or hostile
operations.”).
5
Signal
Function and Examples of Use
Cf.
Supports the proposition by analogy, i.e., discusses a different proposition that is sufficiently
similar to support the original proposition
A person must engage in acts of espionage in the zone of operations of a belligerent to be
considered a spy. “Zone of operations” has been construed broadly to include areas
supporting the war effort.6
6 Cf. Ex parte Quirin, 317 U.S. 1, 37 (1942) (“The law of war cannot rightly treat those
agents of enemy armies who enter our territory, armed with explosives intended for the
destruction of war industries and supplies, as any the less belligerent enemies than are
agents similarly entering for the purpose of destroying fortified places or our Armed
Forces.”).
Refer to
Refers to another manual section that supports or elaborates on the proposition
Certain categories of persons are not members of the armed forces, but are nonetheless
authorized to support the armed forces in the fighting:
• persons authorized to accompany the armed forces, but who are not members
thereof;7
7 Refer to § 4.15 (Persons Authorized to Accompany the Armed Forces).
Compare
Refers to another manual section that is analogous to the proposition
Persons authorized to accompany the armed forces who provide security against criminal
elements generally would not be viewed as taking a direct part in hostilities (and do not
forfeit their protection from being made the object of attack).269
269 Compare § 4.23.1 (Police as Civilians).
Consider
Identifies a treaty that relates to the proposition but to which the United States is not a Party
(e.g., AP I)
Under international law, every treaty in force is binding upon the Parties to it and must
be performed by them in good faith.10
10 Consider VCLT art. 26 (“Every treaty in force is binding upon the parties to it and
must be performed by them in good faith.”).
For
Illustrates the proposition with an example drawn from historical practice
example,
Adjusting the timing of an attack may reduce the risk of incidental harm. For example,
attacking a military objective when civilians are less likely to be present may be
appropriate.11
11 For example, FINAL REPORT ON THE PERSIAN GULF WAR 100 (noting that during
Operation DESERT STORM “attacks on known dual (i.e., military and civilian) use
facilities normally were scheduled at night, because fewer people would be inside or on
the streets outside.”).
6
Signal
Function and Examples of Use
e.g.,
Added to any of the other signals when the cited authority is one of several authorities (some
of which remain uncited) that stand for the same proposition
International humanitarian law is an alternative term for the law of war that may be
understood to have the same substantive meaning as the law of war.12
12 See, e.g., Overview of the Amendment to the Convention on the Physical Protection of
Nuclear Material, 6, Enclosure to Condoleezza Rice, Letter of Submittal, Jun. 11, 2007,
MESSAGE FROM THE PRESIDENT OF THE UNITED STATES TRANSMITTING AMENDMENT
TO THE CONVENTION ON THE PHYSICAL PROTECTION OF NUCLEAR MATERIAL (THE
“AMENDMENT”). A CONFERENCE OF STATES PARTIES TO THE CONVENTION ON THE
PHYSICAL PROTECTION OF NUCLEAR MATERIAL, ADOPTED ON OCTOBER 28, 1979,
ADOPTED THE AMENDMENT ON JULY 8, 2005, AT THE INTERNATIONAL ATOMIC ENERGY
AGENCY IN VIENNA, TREATY DOC. 110-6, 6 (2007) (“(2) The United States of America
understands that the term ‘international humanitarian law’ in Paragraph 5 of the
Amendment (Article 2 of the Convention on the Physical Protection of Nuclear Material,
as amended) has the same substantive meaning as the law of war.”).
1.3 DEFINITION OF THE LAW OF WAR
For the purposes of this manual, the law of war is that part of international law that
regulates the resort to armed force; the conduct of hostilities and the protection of war victims in
both international and non-international armed conflict; belligerent occupation; and the
relationships between belligerent, neutral, and non-belligerent States.6
For the purposes of this manual, the law of war comprises treaties and customary
international law applicable to the United States.7
1.3.1 Law of War - Notes on Terminology.
1.3.1.1 Different Definitions of the Law of War. The law of war may be defined
slightly differently in other publications. For example, DoD issuances have defined the law of
war more narrowly than the definition discussed in this section (e.g., by omitting reference to
that part of international law that regulates the resort to armed force).8
6 Refer to § 3.2 (Situations to Which the Law of War Applies).
7 Refer to § 1.7 (Treaties); § 1.8 (Customary International Law).
8 For example, DOD DIRECTIVE 2310.01E, DoD Detainee Program, 14 (Aug. 19, 2014) (“law of war. The part of
international law that regulates the conduct of hostilities and the protection of victims of armed conflict in both
international and non-international armed conflict and occupation, and that prescribes the rights and duties of
neutral, non-belligerent, and belligerent states. It is often called the ‘law of armed conflict’ or ‘international
humanitarian law,’ and is specifically intended to address the circumstances of armed conflict. It encompasses all
international law applicable to the conduct of military operations in armed conflicts that is binding on the United
States or its individual citizens, including treaties and international agreements to which the United States is a party
(e.g., the Geneva Conventions of 1949), and applicable customary international law.”); DOD DIRECTIVE 2311.01E,
DoD Law of War Program, ¶3.1 (May 9, 2006, Certified Current as of Feb. 22, 2011) (“Law of War. That part of
7
1.3.1.2 Law of War versus International Humanitarian Law and Law of Armed
Conflict. The law of war is often called the law of armed conflict. Both terms can be found in
DoD directives and training materials. International humanitarian law is an alternative term for
the law of war that may be understood to have the same substantive meaning as the law of war.9
In other cases, international humanitarian law is understood more narrowly than the law of war
(e.g., by understanding international humanitarian law not to include the law of neutrality).10
1.3.2 The Law of War’s Relationship to Other Bodies of Law. An issue that often
confronts law of war practitioners is the relationship of the law of war to other bodies of law,
especially when rules in those bodies of law may appear to conflict with rules reflected in the
law of war. These apparent conflicts are often resolved by considering the principle that the law
of war is the lex specialis governing armed conflict.11 How a law of war rule relates to a
particular rule that is not grounded in the law of war may depend on the specific legal rule in
question.
In general, the law of war may relate to other bodies of law through: (1) law of war rules
superseding rules in other bodies of law with respect to armed conflict; (2) construing the rules in
other bodies of law to avoid conflict with law of war rules; (3) law of war rules informing the
content of general standards in other bodies of law, should such standards be construed to apply
international law that regulates the conduct of armed hostilities. It is often called the ‘law of armed conflict.’ The
law of war encompasses all international law for the conduct of hostilities binding on the United States or its
individual citizens, including treaties and international agreements to which the United States is a party, and
applicable customary international law.”).
9 See, e.g., Overview of the Amendment to the Convention on the Physical Protection of Nuclear Material, 6,
Enclosure to Condoleezza Rice, Letter of Submittal, Jun. 11, 2007, MESSAGE FROM THE PRESIDENT OF THE UNITED
STATES TRANSMITTING AMENDMENT TO THE CONVENTION ON THE PHYSICAL PROTECTION OF NUCLEAR MATERIAL
(THE “AMENDMENT”). A CONFERENCE OF STATES PARTIES TO THE CONVENTION ON THE PHYSICAL PROTECTION OF
NUCLEAR MATERIAL, ADOPTED ON OCTOBER 28, 1979, ADOPTED THE AMENDMENT ON JULY 8, 2005, AT THE
INTERNATIONAL ATOMIC ENERGY AGENCY IN VIENNA, TREATY DOC. 110-6, 6 (2007) (“(2) The United States of
America understands that the term ‘international humanitarian law’ in Paragraph 5 of the Amendment (Article 2 of
the Convention on the Physical Protection of Nuclear Material, as amended) has the same substantive meaning as
the law of war.”); FRITS KALSHOVEN & LIESBETH ZEGVELD, CONSTRAINTS ON THE WAGING OF WAR: AN
INTRODUCTION TO INTERNATIONAL HUMANITARIAN LAW 11 (International Committee of the Red Cross, 3rd ed.,
2001) (“The law of war nowadays is often referred to by a phrase better suited to express its object and purpose,
such as ‘international humanitarian law applicable in armed conflict’ or ‘humanitarian law’ - we shall be using these
terms interchangeably, as we do with ‘war’ and ‘armed conflict’.”).
10 Christopher Greenwood, Historical Development and Legal Basis, in DIETER FLECK, THE HANDBOOK OF
HUMANITARIAN LAW IN ARMED CONFLICTS 9 (¶102) (1999) (“The term ‘international humanitarian law’ is of
relatively recent origin and does not appear in the Geneva Conventions of 1949. … International humanitarian law
thus includes most of what used to be known as the laws of war, although strictly speaking some parts of those laws,
such as the law of neutrality, are not included since their primary purpose is not humanitarian.”).
11 See, e.g., Mary McLeod, Acting Legal Adviser, Department of State, Opening Statement at 53rd Session of the
U.N. Committee Against Torture, Nov. 3 - 28, 2014, Nov. 12, 2014 (noting that “the law of armed conflict is the
controlling body of law with respect to the conduct of hostilities and the protection of war victims,”); U.S.
Delegation to U.N. General Assembly Third Committee, Statement Clarifying Legal Points of Importance, 2004
DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 331 (“Third, with respect to [preambular paragraph
(‘PP’)] 4 and PP6, references to human rights law during armed conflict by necessity refer only to those provisions,
if any, that may be applicable. As may be well known, it is the position of the United States Government that the
Law of War is the lex specialis governing armed conflict.”) (amendment in original).
8
to armed conflict; and (4) law of war treaties explicitly incorporating concepts from other bodies
of law.
In some cases, it may be difficult to distinguish between these approaches, and different
entities may apply different approaches to achieve the same result.12 Although there are different
approaches and although the ultimate resolution may depend on the specific rules and context,
the law of war, as the lex specialis of armed conflict, is the controlling body of law with regard
to the conduct of hostilities and the protection of war victims.13
1.3.2.1 The Law of War as the Lex Specialis Governing Armed Conflict. The
maxim lex specialis derogat legi generali means that “[a]s a rule the special rule overrides the
general law.”14 The rule that is more specifically directed towards the action receives priority
because it takes better account of the particular features of the context in which the law is to be
applied, thus creating a more equitable result and better reflecting the intent of the authorities
that have made the law.15
The law of war has been developed with special consideration of the circumstances of
war and the challenges inherent in its regulation by law. Thus, for example, the exigencies of
armed conflict cannot justify violating the law of war.16 Moreover, lawmakers sometimes have
12 Report of the International Law Commission, Fifty-sixth session (3 May-4 June and 5 July-6 August 2004), U.N.
Doc. A/59/10 ¶304 (2004) (“In introducing the part of the study concerning the function and scope of the lex
specialis rule, the Chairman stressed several points. First, he emphasized that recourse to the lex specialis rule was
an aspect of legal reasoning that was closely linked to the idea of international law as a legal system. The lex
specialis maxim sought to harmonize conflicting standards through interpretation or establishment of definite
relationships of priority between them. In fact, he said, it was often difficult to distinguish between these two
aspects of the functioning of the technique: the interpretation of a special law in the light of general law, and the
setting aside of the general law in view of the existence of a conflicting specific rule. … The adoption of a systemic
view was important precisely in order to avoid thinking of lex specialis in an overly formal or rigid manner. Its
operation was always conditioned by its legal-systemic environment.”).
13 Observations of the United States of America on the Human Rights Committee’s Draft General Comment 35:
Article 9, June 10, 2014, ¶20 (“While the United States acknowledges that difficult questions arise regarding the
applicability of international human rights law in situations of armed conflict, the draft does not accord sufficient
weight to the well-established principle that international humanitarian law, as the lex specialis of armed conflict, is
the controlling body of law with regard to the conduct of hostilities and the protection of war victims.”).
14 Colleanu v. German State, German-Rumanian Mixed Arbitral Tribunal, Jan. 12, 1929, reprinted in H.
LAUTERPACHT, V INTERNATIONAL LAW REPORTS 438 (1929). See also GROTIUS, LAW OF WAR & PEACE 428
(2.16.29.1) (“[A]mong agreements which are equal in respect to the qualities mentioned, that should be given
preference which is most specific and approaches most nearly to the subject at hand; for special provisions are
ordinarily more effective than those that are general”).
15 U.N. International Law Commission, Conclusions of the work of the Study Group on the Fragmentation of
International Law: Difficulties arising from the Diversification and Expansion of International Law 2(7) (2006)
(“Rationale of the principle. That special law has priority over general law is justified by the fact that such special
law, being more concrete, often takes better account of the particular features of the context in which it is to be
applied than any applicable general law. Its application may also often create a more equitable result and it may
often better reflect the intent of the legal subjects.”).
16 Refer to § 2.2.2 (Military Necessity and Law of War Rules).
9
considered peacetime rules appropriate to apply during armed conflict, and in certain of these
cases, they have explicitly incorporated such concepts into the law of war.17
Thus, traditionally, the law of war has been described as the only “authoritative rules of
action between hostile armies,” or as superseding ordinary law in the actual theater of military
operations.18 Similarly, law of war treaties have been viewed as a clear example of a lex
specialis in relation to treaties providing peacetime norms concerning the same subjects.19
1.3.2.2 Construing Other Laws to Avoid Conflict With the Law of War. Potential
conflicts between the law of war and other law may be resolved by construing such other law to
avoid conflict with law of war rules.
Underlying this approach is the fact that the law of war is firmly established in customary
international law as a well-developed body of law that is separate from the principles of law
generally applicable in peace.20 Lawmakers have been understood not to amend that well-
developed body of law, absent affirmative evidence of an intention to do so.21 In a similar
17 Refer to § 1.3.2.4 (Explicit Incorporation of Concepts From Other Bodies of Law Into the Law of War).
18 See LIEBER CODE art. 40 (“There exists no law or body of authoritative rules of action between hostile armies,
except that branch of the law of nature and nations which is called the law and usages of war on land.”). See also
WINTHROP, MILITARY LAW & PRECEDENTS 773-74 (“By the term LAW OF WAR is intended that branch of
International Law which prescribes the rights and obligations of belligerents, or—more broadly—those principles
and usages which, in time of war, define the status and relations not only of enemies—whether or not in arms—but
also of persons under military government or martial law and persons simply resident or being upon the theatre of
war, and which authorizes their trial and punishment when offenders. Unlike Military Law Proper, the Law of War
in this country is not a formal written code, but consists mainly of general rules derived from International Law,
supplemented by acts and orders of the military power and a few legislative provisions. In general it is quite
independent of the ordinary law. ‘On the actual theatre of military operations,’ as is remarked by a learned judge,
‘the ordinary laws of the land are superseded by the laws of war. The jurisdiction of the civil magistrate is there
suspended, and military authority and force are substituted.’ Finding indeed its original authority in the war powers
of Congress and the Executive, and thus constitutional in its source, the Law of War may, in its exercise,
substantially supersede for the time even the Constitution itself -as will be hereinafter indicated.”).
19 C. Wilfred Jenks, The Conflict of Law-Making Treaties, 30 BRITISH YEARBOOK OF INTERNATIONAL LAW 401, 446
(1953) (“A clear illustration of [the lex specialis principle’s] applicability is afforded by instruments relating to the
laws of war which, in the absence of evidence of a contrary intention or other special circumstances, must clearly be
regarded as a leges speciales in relation to instruments laying down peace-time norms concerning the same
subjects.”).
20 Edwin D. Williamson, Agent of the United States of America, Preliminary Objections Submitted by the United
States of America, Case Concerning the Aerial Incident of 3 July 1988, I.C.J. (Iran v. United States), 200-01 (Mar. 4,
1991) (“The laws of armed conflict are firmly established in customary international law as a well-developed body
of law separate from the principles of law generally applicable in times of peace.”).
21 See, e.g., Case Concerning Oil Platforms (Iran v. United States), Preliminary Objection, Judgment,1996 I.C.J.
874, 876 (Dissenting Opinion of Vice-President Schwebel) (“It is plain that this is a Treaty which is essentially
concerned with encouraging mutually beneficial trade and investments and closer economic intercourse on the basis
of reciprocal equality of treatment. There is no suggestion of regulating the use of armed force by one party against
the other. … None of these core provisions of the Treaty suggests that attacks by armed forces of one party against
what it treats as military objectives within the jurisdiction of the other party are within the reach of the Treaty. It is
significant as well that the Treaty contains none of the treaty provisions which typically do bear on the international
use of force.”); Written Statement of the Government of the United States of America, 34, Jun. 20, 1995, I.C.J.,
Request by the United Nations General Assembly for an Advisory Opinion on the Legality of the Threat or Use of
Nuclear Weapons (“No international environmental instrument is expressly applicable in armed conflict. No such
10
fashion, for comparison, the GC deliberately excludes from its application the nationals of
certain States in order to avoid creating complications or inconsistencies in procedures should
both the GC and the law applicable to normal diplomatic representation apply.22
In some cases, treaties explicitly clarify that they do not affect States’ rights under the
law of war.23 For example, the 1944 Chicago Convention on civil aviation explicitly provides
that it does not affect the freedom of action of States during armed conflict.24 However, even
when not explicitly stated, infringements on the law of war through international agreements that
primarily address situations other than armed conflict are not to be presumed.25 For example, the
LOS Convention has been interpreted not to impair a State’s rights during armed conflict, even
though this principle is not explicitly stated in the treaty.26 In addition, the International
Convention for the Suppression of the Financing of Terrorism has been understood not to
preclude any State Party to the Convention from conducting any legitimate activity against any
lawful target in accordance with the law of armed conflict.27
instrument expressly prohibits or regulates the use of nuclear weapons. Consequently, such an international
environmental instrument could be applicable only by inference. Such an inference is not warranted because none
of these instruments was negotiated with the intention that it would be applicable in armed conflict or to any use of
nuclear weapons. Further, such an implication is not warranted by the textual interpretation of these instruments.”);
Edwin D. Williamson, Agent of the United States of America, Preliminary Objections Submitted by the United
States of America, Case Concerning the Aerial Incident of 3 July 1988, I.C.J. (Iran v. United States), 207 (Mar. 4,
1991) (“When, 14 years later, the ICAO Assembly drafted Article 3 bis of the Chicago Convention, discussed
above, it was careful to include in the Article a statement that it ‘should not be interpreted as modifying in any way
the rights and obligations of States set forth in the Charter of the United Nations;’ which included the inherent right
of self-defense. The participants at the Montreal conference would have included a similar provision if they had
intended the Montreal Convention to modify the laws of armed conflict, and particularly if they had intended to
address actions by military forces in armed conflict. There is no such provision in the Montreal Convention.”).
22 Refer to § 10.3.3.3 (Nationals of a Neutral State or Co-Belligerent State While Normal Diplomatic Representation
Exists).
23 See, e.g., Convention on the Protection of Submarine Cables, art. 15, Mar. 14, 1884, 24 STAT. 989, 997 (“It is
understood that the stipulations of this Convention shall in no wise affect the liberty of action of belligerents.”).
24 Refer to § 14.1.1.1 (1944 Chicago Convention and Freedom of Action of States During Armed Conflict).
25 Edwin D. Williamson, Agent of the United States of America, Preliminary Objections Submitted by the United
States of America, Case Concerning the Aerial Incident of 3 July 1988, I.C.J., (Iran v. United States) 203 (Mar. 4,
1991) (“Infringements on the laws of armed conflict through international agreements primarily addressing
situations other than armed conflict are not to be presumed. There is no indication that the drafters of the Montreal
Convention intended it to apply to military forces acting in armed conflict. If they had so intended, they would have
had to address a myriad of issues relating to acts by military forces.”); The S.S. Wimbledon, (United Kingdom,
France, Japan v. Germany), Judgment (MM. Anzilotti and Huber, dissenting), 1923 P.C.I.J. (series A) 1, 35, 36 (¶3)
(“In this respect, it must be remembered that international conventions and more particularly those relating to
commerce and communications are generally concluded having regard to normal peace conditions. If, as the result
of a war, a neutral or belligerent State is faced with the necessity of taking extraordinary measures temporarily
affecting the application of such conventions in order to protect its neutrality or for the purposes of national defence,
it is entitled to do so even if no express reservations are made in the convention. This right possessed by all nations,
which is based on generally accepted usage, cannot lose its raison d’être simply because it may in some cases have
been abused;”).
26 Refer to § 13.1.1 (The Law of the Sea During Armed Conflict).
27 United States, Statement on Ratification of International Convention for the Suppression of the Financing
Terrorism, Jun. 26, 2002, 2185 UNTS 611, 612 (“(1) Exclusion of legitimate activities against lawful targets. The
11
In addition to treaties, domestic statutes have also been construed not to violate
international law, including the law of war, if any other construction remains possible.28 Certain
domestic statutes have been interpreted not to apply to situations addressed by the law of war
because such intention was not made clear and unequivocal.29
1.3.2.3 Using the Law of War to Determine the Content of General Standards if
Applied to Armed Conflict. Another way in which the law of war has been applied as lex
specialis is to determine the content of a more general standard with respect to the situation of
armed conflict. For example, the law of war has been used to inform the content of general
authorizations to conduct military operations.30
United States of America understands that nothing in the Convention precludes any State Party to the Convention
from conducting any legitimate activity against any lawful target in accordance with the law of armed conflict.”).
28 The Charming Betsy, 6 U.S. 64, 118 (1804) (Marshall, C.J.) (“It has also been observed that an act of Congress
ought never to be construed to violate the law of nations if any other possible construction remains, and
consequently can never be construed to violate neutral rights or to affect neutral commerce further than is warranted
by the law of nations as understood in this country. These principles are believed to be correct, and they ought to be
kept in view in construing the act now under consideration.”).
29 See, e.g., Walter Dellinger, Assistant Attorney General, United States Assistance to Countries that Shoot Down
Civil Aircraft Involved in Drug Trafficking, Jul. 14, 1994, 18 OPINIONS OF THE OFFICE OF LEGAL COUNSEL 148, 163-
64 (“Specifically, we believe that the section would not apply to the actions of United States military forces acting
on behalf of the United States during a state of hostilities. As discussed above, § 32(b)(2) was intended to
implement the United States’s obligations under the Montreal Convention. That Convention does not appear to
apply to acts of armed forces that are otherwise governed by the laws of armed conflict. … We do not think that
§ 32(b)(2) should be construed to have the surprising and almost certainly unintended effect of criminalizing actions
by military personnel that are lawful under international law and the laws of armed conflict. We note specifically
that the application of § 32(b)(2) to acts of United States military personnel in a state of hostilities could readily lead
to absurdities: for example, it could mean in some circumstances that military personnel would not be able to
engage in reasonable self-defense without subjecting themselves to the risk of criminal prosecution. Unless
Congress by a clear and unequivocal statement declares otherwise, § 32(b)(2) should be construed to avoid such
outcomes. Thus, we do not think the statute, as written, should apply to such incidents as the downing on July 3,
1988 of Iran Air Flight 655 by the United States Navy cruiser Vincennes.”); France Biddle, Attorney General,
Procurements by Commanding Generals in Foreign Theaters of Operations, Nov. 12, 1942, 40 OPINIONS OF THE
ATTORNEY GENERAL 250, 253 (1949) (“The statutes in question do not expressly declare that their provisions are
inapplicable to foreign theaters of operations. But there are conclusive reasons for inferring that the Congress did
not intend them to apply to such theaters. The Supreme Court has long recognized that the power to conduct
military campaigns includes power to procure needed supplies in theaters of operations by whatever methods are
dictated by military necessity. Property may be taken summarily, even from a citizen, if military exigencies make
its seizure reasonably appear to be necessary. It is unthinkable that the Congress attempted, by statutory restrictions,
to abrogate this rule of military necessity, to handicap commanding generals waging war on foreign soil, to limit or
encroach upon the power of the President as Commander in Chief to conduct, through his subordinates, military
campaigns abroad.”) (internal citations omitted).
30 Hamdi v. Rumsfeld, 542 U.S. 507, 519 (2004) (plurality) (“In light of these principles, it is of no moment that the
AUMF does not use specific language of detention. Because detention to prevent a combatant’s return to the
battlefield is a fundamental incident of waging war, in permitting the use of ‘necessary and appropriate force,’
Congress has clearly and unmistakably authorized detention in the narrow circumstances considered here.”). See
also In re Guantanamo Bay Litigation, Respondents’ Memorandum Regarding the Government’s Detention
Authority Relative to Detainees Held at Guantanamo Bay, Misc. No. 08-442, 4 (D.D.C., Mar. 13, 2009) (“The
United States bases its detention authority as to such persons on the Authorization for the Use of Military Force
(‘AUMF’), Pub. L. 107-40, 115 Stat. 224 (2001). The detention authority conferred by the AUMF is necessarily
informed by principles of the laws of war.”).
12
As another example, to the extent that the concept of “due regard” for the safety of civil
aircraft may be deemed to apply during armed conflict, what regard is due would be understood
in terms of the requirements of the law of war.31 Similarly, to the extent that the concept of “due
regard” for the rights of other States under the law of the sea may be deemed to apply during
armed conflict, what regard is due would be understood in terms of the requirements of the law
of war.32
Lastly, even where international courts or commissions have characterized human rights
obligations as applicable during armed conflict, they generally have characterized the content of
those obligations as determined by standards and tests drawn from the law of war.33
1.3.2.4 Explicit Incorporation of Concepts From Other Bodies of Law Into the
Law of War. In some cases, law of war treaties explicitly incorporate concepts from other bodies
of law. For example, the peacetime property law concept of usufruct is made applicable to the
duties of the Occupying States.34 Similarly, the GC explicitly applies a peacetime rule with
respect to the nationals of the Occupying Power who, before the outbreak of hostilities, have
sought refuge in the occupied territory.35 And as another example, Common Article 3 of the
1949 Geneva Conventions incorporates by reference those judicial guarantees that are
recognized as indispensable by civilized peoples.36
1.3.3 Restrictive and Permissive Character of the Law of War. In certain respects, the law
of war may be viewed as prohibitive; in other respects, the law of war may be viewed as
permissive.37
1.3.3.1 Law of War as Prohibitive Law. The law of war that relates to the conduct
of hostilities has generally been viewed as “prohibitive law,” in the sense that it forbids rather
than authorizes certain uses of force.38 For example, the lawfulness of the use of a type of
31 Refer to § 14.1.1.4 (Due Regard for the Safety of Navigation of Civil Aircraft).
32 Refer to § 13.1.1 (The Law of the Sea During Armed Conflict).
33 Refer to § 1.6.3.1 (Relationship Between Human Rights Treaties and the Law of War).
34 Refer to § 11.18.5.2 (Public Real (Immovable) Property That Is Essentially of a Non-Military Nature).
35 Refer to § 11.11.7.2 (Protection of Nationals of the Occupying Power Who, Before the Outbreak of Hostilities,
Have Sought Refuge in the Territory of the Occupied State).
36 Refer to § 8.16 (Criminal Procedure and Punishment).
37 VON GLAHN, THE OCCUPATION OF ENEMY TERRITORY 5 (“Throughout the pages of this study a basic fact will
appear repeatedly: the laws of war, including the rules applicable to belligerent occupation, are in part permissive
and in part prohibitive—a fact that has been overlooked frequently in treatments of the subject.”).
38 See Richard R. Baxter, So-Called ‘Unprivileged Belligerency’: Spies, Guerillas, and Saboteurs, 28 BRITISH YEAR
BOOK OF INTERNATIONAL LAW 323, 324 (1951) (“The law of war is, in the descriptive words of a war crimes
tribunal, ‘prohibitive law’ in the sense that it forbids rather than authorizes certain manifestations of force.”)
(quoting United States v. List, et al. (The Hostage Case), XI TRIALS OF WAR CRIMINALS BEFORE THE NMT 1252);
Gherebi v. Obama, 609 F. Supp. 2d 43, 65 (D.D.C. 2009) (rejecting as “exactly backwards” the “notion that the
Geneva Conventions must specifically enable its signatories to act in a specific manner for a signatory to have the
authority necessary to take such action.”); JOHN WESTLAKE, II INTERNATIONAL LAW 52 (1907) (“These rules are
always restrictive, never permissive in any other sense than that of the absence of prohibition, for law can give no
positive sanction to any act of force of which it cannot secure the employment on the side of justice alone, even if
13
weapon does not depend on an absence of authorization, but, on the contrary, on whether the
weapon is prohibited.39
One rationale for this view is that the rules binding upon States in treaties and customary
law reflect restrictions that they have accepted, and that States are otherwise independent entities
with freedom to act.40 Thus, the authority to take actions under the law of war would be viewed
as emanating from the State’s rights as a sovereign entity rather than from any particular
instrument of international law.
The prohibitive character of the law of war that relates to the conduct of hostilities is also
consistent with the view that jus in bello applies to aggressors and defenders alike. The fact that
an aggressor complies with jus in bello does not justify the legality of its military operations
under jus ad bellum.41
The lack of an express prohibition in treaty law, however, does not necessarily mean that
an action is lawful under jus in bello. When no specific rule applies, the principles of the law of
war form the general guide for conduct during war.42
1.3.3.2 Law of War as Permissive Law. Although the law of war is generally
viewed as “prohibitive law,” in some respects, especially in the context of domestic law, the law
of war may be viewed as permissive or even as a source of authority.43
For example, the principle of military necessity in the customary law of war may be
viewed as justifying or permitting certain acts.44 Similarly, under the law of belligerent
the particular act be not one which the law would prohibit both to the just and to the unjust if it could. Whenever
therefore in speaking of the laws of war it is said that a belligerent may do this or that, it is always only the absence
of prohibition that must be understood.”).
39 Refer to § 6.2.1 (Review of New Types of Weapons).
40 The S.S. Lotus, (France v. Turkey) (Judgment), 1927 P.C.I.J. (series A) No. 10, at 18 (“International law governs
relations between independent States. The rules of law binding upon States therefore emanate from their own free
will as expressed in conventions or by usages generally accepted as expressing principles of law and established in
order to regulate the relations between these co-existing independent communities or with a view to the achievement
of common aims. Restrictions upon the independence of States cannot therefore be presumed.”).
41 Refer to § 3.5.2 (Jus in Bello and Jus ad Bellum Generally Operate Independently of One Another).
42 Refer to § 2.1.2.2 (Law of War Principles as a General Guide).
43 See, e.g., Eric Holder, Attorney General, Remarks at Northwestern University School of Law, Mar. 5, 2012, 2012
DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 577, 581 (“It is preferable to capture suspected
terrorists where feasible—among other reasons, so that we can gather valuable intelligence from them—but we must
also recognize that there are instances where our government has the clear authority—and, I would argue, the
responsibility—to defend the United States through the appropriate and lawful use of lethal force. This principle has
long been established under both U.S. and international law. In response to the attacks perpetrated—and the
continuing threat posed—by al Qaeda, the Taliban, and associated forces, Congress has authorized the President to
use all necessary and appropriate force against those groups. Because the United States is in an armed conflict, we
are authorized to take action against enemy belligerents under international law. The Constitution empowers the
President to protect the nation from any imminent threat of violent attack. And international law recognizes the
inherent right of national self-defense. None of this is changed by the fact that we are not in a conventional war.”).
44 Refer to § 2.2.1 (Military Necessity as a Justification).
14
occupation, the fact of occupation is the basis for the Occupying Power to exercise authority over
the occupied territory.45 In addition, law of war treaties also sometimes recognize States’
authorities in war.46
1.3.4 Purposes of the Law of War. The main purposes of the law of war are:
• protecting combatants, noncombatants, and civilians from unnecessary suffering;47
• providing certain fundamental protections for persons who fall into the hands of the
enemy, particularly prisoners of war, civilians, and military wounded, sick, and
shipwrecked;48
• facilitating the restoration of peace;49
• assisting military commanders in ensuring the disciplined and efficient use of military
force;50 and
• preserving the professionalism and humanity of combatants.51
1.4 OBJECT AND NATURE OF WAR
Understanding the object and nature of war is important in understanding and applying
the law of war.52
45 Refer to § 11.2.1 (Military Occupation as a Fact).
46 See, e.g., GPW art. 21 (recognizing that “[t]he Detaining Power may subject prisoners of war to internment.”);
HAGUE IV REG. art. 24 (recognizing that “[r]uses of war and the employment of measures necessary for obtaining
information about the enemy and the country are considered permissible.”).
47 Refer to § 2.3 (Humanity).
48 Refer to § 7.5 (Humane Treatment and Care of Enemy Military Wounded, Sick, and Shipwrecked in the Power of
a Party to the Conflict); § 8.2 (Humane Treatment of Detainees); § 9.5 (Humane Treatment and Basic Protections
for POWs); § 10.5 (Humane Treatment and Other Basic Protections for Protected Persons).
49 Refer to § 12.1.2.2 (Non-Hostile Relations to Facilitate the Restoration of Peace).
50 Refer to § 18.2.1 (Reinforcing Military Effectiveness).
51 Refer to § 2.6 (Honor).
52 DEPARTMENT OF THE ARMY PAMPHLET 27-161-2, II International Law, 1 (Oct. 23, 1962) (“An understanding of
the laws of war necessitates an understanding of ‘war’ itself. It is the phenomenon of war which these laws are
attempting in some manner to control.”). See also Adam Roberts, Land Warfare: From Hague to Nuremberg, in
MICHAEL HOWARD, GEORGE J. ANDREOPOULOUS, & MARK A. SHULMAN, THE LAWS OF WAR: CONSTRAINTS ON
WARFARE IN THE WESTERN WORLD 117 (1994) (“The laws of war are strange not only in their subject matter, which
to many people seems a contradiction in terms, but also in their methodology. There is little tradition of disciplined
and reasoned assessment of how the laws of war have operated in practice. Lawyers, academics, and diplomats have
often been better at interpreting the precise legal meaning of existing accords, or at devising new law, than they have
been at assessing the performance of existing accords or at generalizing about the circumstances in which they can
or cannot work. In short, the study of law needs to be integrated with the study of history; if not, it is inadequate.”).
15
1.4.1 Object of War. The object of war has been understood to be the submission of the
enemy as quickly and efficiently as possible.53 The military defeat of the enemy in war is
intended to advance political objectives.54 Even where those political objectives are limited, the
object of war is nonetheless to ensure the submission of the enemy as quickly and efficiently as
possible.55
The object of war informs the principle of military necessity and what uses of force may
be justified in war.56 Nevertheless, the law of war limits what uses of force the object of war
may justify.57
1.4.2 Nature of War.
1.4.2.1 Nature of War - Violence and Suffering. War has been described as a
violent clash of interests characterized by the use of force.58 The fact that violence is an essential
53 See 1940 RULES OF LAND WARFARE ¶22 (“The object of war is to bring about the complete submission of the
enemy as soon as possible by means of regulated violence.”); 1914 RULES OF LAND WARFARE ¶10 (same).
54 George H. Aldrich, Deputy Legal Adviser, Department of State, Human Rights in Armed Conflict: Development
of the Law, Apr. 13, 1973, 68 DEPARTMENT OF STATE BULLETIN, 876, 880 (Jun. 18, 1973) (“What we have seen is
all too clearly a general acceptance of the view that modern war is aimed not merely at the enemy’s military forces
but at the enemy’s willingness and ability to pursue its war aims. Thus, in the Second World War the enemy’s will
to fight and his capacity to produce weapons were primary targets; and saturation bombing, blockade of food
supplies, and indiscriminate terror weapons such as the German V bombs, were all brought to bear on those targets.
In Viet-Nam political, rather than military, objectives were even more dominant. Both sides had as their goal not
the destruction of the other’s military forces but the destruction of the will to continue the struggle.”); United States
v. von Leeb, et al. (The High Command Case), XI TRIALS OF WAR CRIMINALS BEFORE THE NMT 485 (“War is the
exerting of violence by one state or politically organized body against another. In other words, it is the
implementation of a political policy by means of violence.”); CARL VON CLAUSEWITZ, ON WAR 87 (1989) (“We see,
therefore, that war is not merely an act of policy but a true political instrument, a continuation of political
intercourse, carried on with other means. What remains peculiar to war is simply the peculiar nature of its means.
War in general, and the commander in any specific instance, is entitled to require that the trend and designs of policy
shall not be inconsistent with these means. That, of course, is no small demand; but however much it may affect
political aims in a given case, it will never do more than modify them. The political object is the goal, war is the
means of reaching it, and means can never be considered in isolation from their purpose.”).
55 For example, General Colin L. Powell, Chairman of the Joint Chiefs of Staff, U.S. Forces: Challenges Ahead, 71
FOREIGN AFFAIRS 32, 37 (1992) (explaining that despite the limited political objectives of the 1991 Gulf War, the
United States “did use overwhelming force quickly and decisively.”).
56 Refer to § 2.2.1 (Military Necessity as a Justification); § 2.2.3.1 (Consideration of the Broader Imperatives of
Winning the War).
57 Refer to § 2.2.2 (Military Necessity and Law of War Rules).
58 DEPARTMENT OF THE ARMY FIELD MANUAL 3-24, Counterinsurgency, 1-1 (¶1-1) (Dec. 2006) (“Insurgency and
counterinsurgency (COIN) are complex subsets of warfare. Globalization, technological advancement, urbanization,
and extremists who conduct suicide attacks for their cause have certainly influenced contemporary conflict;
however, warfare in the 21st century retains many of the characteristics it has exhibited since ancient times.
Warfare remains a violent clash of interests between organized groups characterized by the use of force. Achieving
victory still depends on a group’s ability to mobilize support for its political interests (often religiously or ethnically
based) and to generate enough violence to achieve political consequences. Means to achieve these goals are not
limited to conventional forces employed by nation-states.”); MARINE CORPS DOCTRINAL PUBLICATION 1,
Warfighting, 3 (Jun. 20, 1997) (explaining that war is “a violent clash of interests between or among organized
groups characterized by the use of military force.”).
16
element of war has been viewed as important in understanding the nature of war.59 The violent
nature of war has also meant that suffering has been an unfortunate and tragic, but unavoidable
consequence of war.60
Law of war treaties such as the Hague and Geneva Conventions have been negotiated
with the understanding that suffering and destruction are unavoidably part of war.61 But these
treaties and the principle of humanity seek to reduce unnecessary suffering and destruction.62
1.4.2.2 Nature of War - Limited and Unreliable Information - “Fog of War”.
During war, information is often limited and unreliable.63 The uncertainty of information in war
results from the chaotic nature of combat and from the opposing sides’ efforts to deceive one
another, which generally is not prohibited by the law of war.64
The limited and unreliable nature of information available during war has influenced the
development of the law of war. For example, it affects how the principle of military necessity is
59 MARINE CORPS DOCTRINAL PUBLICATION 1, Warfighting, 14 (Jun. 20, 1997) (“War is among the greatest horrors
known to humanity; it should never be romanticized. The means of war is force, applied in the form of organized
violence. It is through the use of violence, or a credible threat of violence, that we compel our enemy to do our will.
Violence is an essential element of war, and its immediate result is bloodshed, destruction, and suffering. While the
magnitude of violence may vary with the object and means of war, the violent essence of war will never change.
Any study of war that neglects this basic truth is misleading and incomplete.”).
60 For example, Friedrich II, Letter to Lord Marischal, Nov. 23, 1758 reprinted in THOMAS CARLYLE, V HISTORY OF
FRIEDERICH II OF PRUSSIA: CALLED FREDERICK THE GREAT 386 (1865) (“Our Campaign is over; and there has
nothing come of it on one side or the other, but the loss of a great many worthy people, the misery of a great many
poor soldiers crippled forever, the ruin of some Provinces, the ravage, pillage and conflagration of some flourishing
Towns. Exploits these, which make humanity shudder: … .”).
61 Edward R. Cummings, Acting Assistant Legal Adviser for Politico-Military Affairs, Remarks at Symposium at
Brooklyn Law School, Sept. 25, 1982, III CUMULATIVE DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL
LAW 1981-88 3421, 3422 (“The Conventions referred to today, such as the Hague and Geneva Conventions, are
important ones and are strongly supported by the United States. They have helped reduce the suffering caused by
wars. But one should not ask the impossible of these agreements. They were not intended to make war ‘humane’ or
to ban war, or to make wars more difficult to fight. They were modestly intended to reduce the inhumanity and
barbarity of war when militarily possible. Anyone who has read the negotiating records of these old agreements will
note that they were largely negotiated by the military. In fact, the first agreement of this kind, the St. Petersburg
Declaration, was agreed to by a military commission. Unrealistic provisions which just would not be accepted or
respected in battle were not favored.”).
62 Refer to § 2.3 (Humanity).
63 See, e.g., United States v. List, et al. (The Hostage Case), XI TRIALS OF WAR CRIMINALS BEFORE THE NMT 1297
(“The course of a military operation by the enemy is loaded with uncertainties, such as the numerical strength of the
enemy, the quality of his equipment, his fighting spirit, the efficiency and daring of his commanders, and the
uncertainty of his intentions.”); CARL VON CLAUSEWITZ, ON WAR 140 (1989) (“the general unreliability of all
information presents a special problem in war: all action takes place so to speak, in a kind of twilight, which like
fog or moonlight, often tends to make things grotesque and larger than they really are.”).
64 Refer to § 5.25 (Ruses of War and Other Lawful Deceptions).
17
applied.65 The limited and unreliable nature of information available during war also is
recognized in the law of war’s standards for how persons are to assess information.66
1.5 “WAR” AS A LEGAL CONCEPT
“War” is sometimes used as a legal concept, i.e., the application or operation of a legal
rule may depend on the existence of a “war,” “armed conflict,” or “hostilities.” As a legal
concept, “war” has traditionally been viewed as a condition in which a State is prosecuting its
rights by military force, usually against another State. However, the precise definition of “war”
often depends on the specific legal context in which it is used.
1.5.1 Traditional Conception of War Under International Law. As international law
began to regulate “war,” “hostilities,” and “armed conflict,” it became necessary to determine
what “war” is for the purpose of triggering those legal obligations.67
As a legal concept, war has usually been described as a condition or state that applies
more broadly than only the mere employment of force or the mere commission of acts of
violence.68
When treated as a legal concept, “war” has been associated with a State’s use of force to
vindicate its rights (principally, its inherent right of self-defense) under international law.69
65 Refer to § 2.2.3 (Applying Military Necessity).
66 Refer to § 5.4 (Assessing Information Under the Law of War).
67 See, e.g., Arnold D. McNair, The Legal Meaning of War, and the Relation of War to Reprisals, 11 TRANSACTIONS
OF THE GROTIUS SOCIETY 29, 30 (1925) (“There exist many treaties and other international conventions under which
important obligations arise upon the occurrence of a state of ‘war,’ and as regards which, therefore, either because
the term ‘war’ or some other term connoting war, such as ‘neutrality,’ is used, it becomes essential to know whether
or not a state of war exists at a given point of time. Thus most of the Hague Conventions only come into operation
once a state of war has arisen—for instance, those relating to the Laws and Customs of War on Land, to the Rights
and Duties of Neutrals in Land and Maritime War respectively, to the Bombardment of Ports, Towns and Villages
by Naval Forces, and to the Status of Enemy Merchant Ships at the Outbreak of Hostilities.”).
68 1956 FM 27-10 (Change No. 1 1976) ¶8 (“While it is usually accompanied by the commission of acts of violence,
a state of war may exist prior to or subsequent to the use of force.”); VII MOORE’S DIGEST 153 (“Much confusion
may be avoided by bearing in mind the fact that by the term war is meant not the mere employment of force, but the
existence of the legal condition of things in which rights are or may be prosecuted by force.”); GROTIUS, LAW OF
WAR & PEACE 33 (1.1.2.1) (“war is the condition of those contending by force”).
69 SPAIGHT, AIR POWER AND WAR RIGHTS 2 (“War, after all, is only a means to an end. It is a way of settling an
international difference which diplomacy has failed to adjust and which is not susceptible of treatment by the other
means of pacific settlement, such as inquiry commissions, arbitration, or submission to the Permanent Court of The
Hague. When all else fails, there is no way in which a nation can assert its rights save by going to war. War is the
means by which it vindicates a vital right threatened or infringed by the claim or act of another State. Its object is to
cause the other State to desist from the action or abandon the claim which is the cause of offence. In other words, a
war is fought in order to bring about a change of mind in another State.”); The Prize Cases, 67 U.S. 635, 666 (1863)
(“War has been well defined to be, ‘That state in which a nation prosecutes its right by force.’”) (quoting EMERICH
DE VATTEL, DROIT DE GENS (LAW OF NATIONS) (1760)); LIEBER CODE art. 30 (“Ever since the formation and
coexistence of modern nations, and ever since wars have become great national wars, war has come to be
acknowledged not to be its own end, but the means to obtain great ends of state, or to consist in defense against
18
Traditionally, war has often been described as a legal condition between two or more
States.70 However, certain law of war rules apply to non-international armed conflicts (such as
intrastate conflicts or conflicts between a State and a non-State armed group).71
1.5.2 Different Definitions of “War” for Different Legal Purposes. There is no single
legal definition of “war,” “hostilities,” or “armed conflict,” and the definition of these terms has
varied in both domestic and international law.
In domestic law, “war,” “hostilities,” and “armed conflict” have been interpreted
differently depending on the specific legal context at issue.72 For example, under the
Constitution, Congress has the power to “declare war.”73 Thus, “war” might be interpreted to
determine whether a military operation constitutes “war” in this sense.74 Similarly, the War
Powers Resolution states certain requirements that are triggered when U.S. forces are introduced
wrong; and no conventional restriction of the modes adopted to injure the enemy is any longer admitted; but the law
of war imposes many limitations and restrictions on principles of justice, faith, and honor.”).
70 1956 FM 27-10 (Change No. 1 1976) ¶8a (“War may be defined as a legal condition of armed hostility between
States. While it is usually accompanied by the commission of acts of violence, a state of war may exist prior to or
subsequent to the use of force. The outbreak of war is usually accompanied by a declaration of war (see par. 20).
Instances of armed conflict without declaration of war may include, but are not necessarily limited to, the exercise of
armed force pursuant to a recommendation, decision, or call by the United Nations, in the exercise of the inherent
right of individual or collective self-defense against armed attack, or in the performance of enforcement measures
through a regional arrangement, or otherwise, in conformity with appropriate provisions of the United Nations
Charter.”); LAUTERPACHT, II OPPENHEIM’S INTERNATIONAL LAW 202 (§54) (“War is a contention between two or
more States through their armed forces, for the purpose of overpowering each other and imposing such conditions of
peace as the victor pleases.”); LIEBER CODE art. 20 (“Public war is a state of armed hostility between sovereign
nations or governments. It is a law and requisite of civilized existence that men live in political, continuous
societies, forming organized units, called states or nations, whose constituents bear, enjoy, and suffer, advance and
retrograde together, in peace and in war.”).
71 Refer to § 3.3.1 (International Armed Conflict and Non-International Armed Conflict).
72 See, e.g., Fred K. Green, The Concept of “War” and the Concept of “Combatant” in Modern Conflicts, 10
MILITARY LAW AND LAW OF WAR REVIEW 267, 269 (1971) (“[I]n US municipal law, the existence of “war” and its
beginning and termination is a question of objective fact determined for different purposes by different agencies of
the sovereign. There has been no apparent effort to coordinate federal law so as to permit establishment of fixed
criteria that would be identified and applicable for all purposes. The tremendous variations in result that this
situation produces renders meaningless any attempt to generalize with respect to established criteria.”).
73 U.S. CONSTITUTION art. I, § 8.
74 Caroline D. Krass, Principal Deputy Assistant Attorney General, Authority to use Military Force in Libya, 8 (Apr.
1, 2011) (“[T]he historical practice of presidential military action without congressional approval precludes any
suggestion that Congress’s authority to declare war covers every military engagement, however limited, that the
President initiates. In our view, determining whether a particular planned engagement constitutes a ‘war’ for
constitutional purposes instead requires a fact-specific assessment of the ‘anticipated nature, scope, and duration’ of
the planned military operations. Haiti Deployment, 18 Op. O.L.C. at 179.”).
19
into “hostilities.”75 Other statutes may require a determination that conduct has occurred
“[w]hen the United States is at war” or during “time of war.”76
Under international law, “war,” “hostilities,” and “armed conflict” may also be
interpreted with different purposes in mind.77 A state of “war” can affect what duties States that
are not participating in the conflict have under the law of neutrality.78 A state of “war” can affect
whether peacetime treaties between two States continue to apply. Most importantly for the
purposes of this manual, the terms “war” and “armed conflict” are used to describe when jus in
bello rules apply.79
1.6 LAW OF WAR DISTINGUISHED FROM CERTAIN TOPICS
The law of war may be distinguished from the following topics: (1) operational law; (2)
arms control; (3) human rights treaties; (4) the Just War Tradition; (5) rules of engagement; and
(6) the Code of Conduct for U.S. Armed Forces.
1.6.1 Operational Law. The law of war is an important part of, but not the entirety of,
operational law. Operational law consists of that body of domestic, foreign, and international
law that specifically pertains to the activities of military forces across the entire conflict
spectrum. Operational law includes diverse legal disciplines, such as military justice,
administrative and civil law, legal assistance, claims, procurement law, national security law,
fiscal law, and the law of war.80
75 See 50 U.S.C. § 1543(a)(1) (“In the absence of a declaration of war, in any case in which United States Armed
Forces are introduced— (1) into hostilities or into situations where imminent involvement in hostilities is clearly
indicated by the circumstances; … the President shall submit within 48 hours to the Speaker of the House of
Representatives and to the President pro tempore of the Senate a report, in writing, setting forth … .”).
76 See, e.g., 10 U.S.C. § 843(f) (“When the United States is at war, the running of any statute of limitations
applicable to [certain offenses]… is suspended until three years after the termination of hostilities as proclaimed by
the President or by a joint resolution of Congress.”); 10 U.S.C. § 906 (“Any person who in time of war is found
lurking as a spy or acting as a spy in or about any place, vessel, or aircraft, within the control or jurisdiction of any
of the armed forces, or in or about any shipyard, any manufacturing or industrial plant, or any other place or
institution engaged in work in aid of the prosecution of the war by the United States, or elsewhere, shall be tried by a
general court-martial or by a military commission and on conviction shall be punished by death. This section does
not apply to a military commission established under chapter 47A of this title.”).
77 JULIUS STONE, LEGAL CONTROLS OF INTERNATIONAL CONFLICT 312 (1954) (“[T]he question ‘War or No War?’
may have to be answered differently according to the purposes for which an answer is sought. One answer, for
example, may be indicated for the purposes of the rules for the mitigation of suffering; another for those governing
war supplies to belligerents from neutral governments, or governing blockade or contraband.”).
78 Refer to § 15.2.1 (Armed Conflict and the Application of the Law of Neutrality).
79 Refer to § 3.4 (When Jus in Bello Rules Apply).
80 THE JUDGE ADVOCATE GENERAL’S SCHOOL, U.S. ARMY, OPERATIONAL LAW HANDBOOK JA 422 1-1 (1997)
(“[Operational law is] [t]hat body of domestic, foreign, and international law that impacts specifically upon the
activities of U.S. Forces across the entire operational spectrum. Operational law is the essence of the military legal
practice. It is a collection of diverse legal and military skills, focused on military operations. It includes military
justice, administrative and civil law, legal assistance, claims, procurement law, environmental law, national security
law, fiscal law, international law, host nations law, and the law of war. In short, operational law is a unique blend of
20
1.6.2 Arms Control. Arms control is a broad term that includes a variety of efforts to
reduce the numbers, types, performance characteristics, proliferation, testing, or other aspects of
certain categories of weapons. Arms control usually proceeds through bilateral or multilateral
treaties. Arms control can also include non-binding political commitments, as well as reciprocal
unilateral statements of intention or policy. The overall goals of arms control are to reduce: (1)
the likelihood of war; (2) the consequences of war, should it occur; and (3) the costs of preparing
for war.
Arms control is closely related to other concepts. For example, “non-proliferation” refers
specifically to efforts to restrict the spread of weapons (in particular, weapons of mass
destruction).
“Disarmament” refers to efforts to eliminate entirely, rather than to restrict, a
particular category of weapon. And sometimes States accept “confidence-building measures” (or
confidence, security, and transparency-building measures) that do not directly reduce the
quantity or quality of armaments, but rather increase States’ certainty that ambiguous activities
by other States are not secret actions in violation of arms control obligations.
Arms control and the law of war frequently overlap in treaties. For example, the CCW
Protocol IV on Blinding Laser Weapons has both arms control and law of war provisions.81
Similarly, the Chemical Weapons Convention prohibits, inter alia, the development and
stockpiling of chemical weapons, but it is also directly relevant to the law of war because it
prohibits the use of chemical weapons in all circumstances.82
1.6.3
Human Rights Treaties.83
Human rights treaties address primarily the obligations
of governments with respect to the rights of individuals, including their own nationals.84 For
every source of law that has application within the operational context. … Because the definition of operational law
is so broad, ample statutory and regulatory references serve to establish the substance of the practice.”).
81 Refer to § 19.21.5 (CCW Protocol IV on Blinding Laser Weapons).
82 Refer to § 6.8.3.2 (Prohibitions With Respect to Chemical Weapons).
83 This section focuses on human rights treaties and not other sources of international human rights law. See, e.g.,
Catherine Amirfar, Counselor for International Law, Department of State, Statement at 53rd Session of the U.N.
Committee Against Torture, Nov. 3 - 28, 2014, Nov. 12, 2014 (“For example, the prohibition against torture is
customary international law binding on all nations everywhere, at all times.”); U.N. International Law Commission,
State responsibility: Comments and observations received from Governments, U.N. Doc. A/CN.4/488, 133 (Mar.
25, 1998) (“United States of America Subparagraph (e) [which would reflect a prohibition against conduct by way
of countermeasures in contravention of a peremptory norm of general international law] similarly does not provide
useful guidance in determining whether a countermeasure would be permissible. Just as there is little agreement
with respect to ‘basic’ human rights and political and economic ‘coercion’, the content of peremptory norms is
difficult to determine outside the areas of genocide, slavery and torture.”).
84 See, e.g., Jimmy Carter, United Nations Remarks on Signing International Covenants on Human Rights, 1977-II
PUBLIC PAPERS OF THE PRESIDENTS 1734 (“The Covenant on Civil and Political Rights concerns what governments
must not do to their people, and the Covenant on Economic, Social and Cultural Rights concerns what governments
must do for their people. By ratifying the Covenant on Civil and Political Rights, a government pledges, as a matter
of law, to refrain from subjecting its own people to arbitrary imprisonment or execution or to cruel or degrading
treatment. It recognizes the right of every person to freedom of thought, freedom of conscience, freedom of
religion, freedom of opinion, freedom of expression, freedom of association, and the rights of peaceful assembly,
and the right to emigrate from that country.”).
21
example, governments must refrain from subjecting individuals to arbitrary detention, to
arbitrary deprivation of life, or to cruel, inhuman, or degrading treatment or punishment.85
As a general matter, human rights treaties have been described as primarily applicable to
the relationship between a State and individuals in peacetime.86 Some human rights treaties also
provide for derogation from certain provisions in emergency situations.87
Law of war treaties have been described as chiefly concerned with the conditions
particular to armed conflict and the relationship between a State and nationals of the enemy
State.88 Law of war treaties generally do not provide for derogation because necessity is not a
basis for derogating from law of war rules.89
1.6.3.1 Relationship Between Human Rights Treaties and the Law of War. In
some circumstances, the rules in the law of war and the rules in human rights treaties may appear
to conflict; these apparent conflicts may be resolved by the principle that the law of war is the lex
specialis during situations of armed conflict, and, as such, is the controlling body of law with
regard to the conduct of hostilities and the protection of war victims.90
85 International Covenant on Civil and Political Rights, art. 9(1), Dec. 19, 1966, 999 UNTS 171, 175 (“Everyone has
the right to liberty and security of person. No one shall be subjected to arbitrary arrest or detention. No one shall be
deprived of his liberty except on such grounds and in accordance with such procedure as are established by law.”);
International Covenant on Civil and Political Rights, art. 6(1), Dec. 19, 1966, 999 UNTS 171, 174 (“Every human
being has the inherent right to life. This right shall be protected by law. No one shall be arbitrarily deprived of his
life.”); International Covenant on Civil and Political Rights, art. 7, Dec. 19, 1966, 999 UNTS 171, 175 (“No one
shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment. In particular, no one shall
be subjected without his free consent to medical or scientific experimentation.”).
86 See, e.g., JEAN PICTET, HUMANITARIAN LAW AND THE PROTECTION OF WAR VICTIMS 15 (1975) (“Admittedly,
human rights embody more general principles while the law of armed conflicts is of a specific and exceptional
nature, coming as it does into operation at the very time when the exercise of human rights is prevented or restricted
by war. But the two legal systems are fundamentally different, for humanitarian law is valid only in the case of an
armed conflict while human rights are essentially applicable in peacetime, and contain derogation clauses in case of
conflict. Moreover, human rights govern relations between the State and its own nationals, the law of war those
between the State and enemy nationals.”).
87 See, e.g., International Covenant on Civil and Political Rights, art. 4(1), Dec. 19, 1966, 999 UNTS 171, 174 (“In
time of public emergency which threatens the life of the nation and the existence of which is officially proclaimed,
the States Parties to the present Covenant may take measures derogating from their obligations under the present
Covenant to the extent strictly required by the exigencies of the situation, provided that such measures are not
inconsistent with their other obligations under international law and do not involve discrimination solely on the
ground of race, colour, sex, language, religion or social origin.”).
88 Christopher Greenwood, Historical Development and Legal Basis, in DIETER FLECK, THE HANDBOOK OF
HUMANITARIAN LAW IN ARMED CONFLICTS 9 (¶102) (1999) (“Human rights law is designed to operate primarily in
normal peacetime conditions, and within the framework of the legal relationship between a state and its citizens.
International humanitarian law, by contrast, is chiefly concerned with the abnormal conditions of armed conflict and
the relationship between a state and the citizens of its adversary, a relationship otherwise based upon power rather
than law.”).
89 Refer to § 2.2.2 (Military Necessity and Law of War Rules).
90 Refer to § 1.3.2 (The Law of War’s Relationship to Other Bodies of Law).
22
For example, the right to challenge the lawfulness of an arrest before a court provided in
Article 9 of the International Covenant on Civil and Political Rights (ICCPR) would appear to
conflict with the authority under the law of war to detain certain persons without judicial process
or criminal charge.91 However, the United States has understood Article 9 of the ICCPR not to
affect a State’s authorities under the law of war, including a State’s authority in both
international and non-international armed conflicts to detain enemy combatants until the end of
hostilities.92 Some international courts or commissions have interpreted the rights conveyed by
human rights treaties in light of the rules of the law of war, as the applicable lex specialis, when
assessing situations in armed conflict.93
On the other hand, during armed conflict, human rights treaties would clearly be
controlling with respect to matters that are within their scope of application and that are not
addressed by the law of war. For example, a time of war does not suspend the operation of the
ICCPR with respect to matters within its scope of application. Therefore, as an illustration,
participation in a war would in no way excuse a State Party to the ICCPR from respecting and
91 International Covenant on Civil and Political Rights, art. 9(4), Dec. 19, 1966, 999 UNTS 171, 176 (“Anyone who
is deprived of his liberty by arrest or detention shall be entitled to take proceedings before a court, in order that that
court may decide without delay on the lawfulness of his detention and order his release if the detention is not
lawful.”).
92 Observations of the United States of America on the Human Rights Committee’s Draft General Comment 35:
Article 9, ¶22, Jun. 10, 2014 (“Given that international humanitarian law is the controlling body of law in armed
conflict with regard to the conduct of hostilities and the protection of war victims, the United States does not
interpret references to ‘detainees’ and ‘detention’ in several paragraphs to refer to government action in the context
of and associated with an armed conflict. For example, paragraph 15 incorrectly implies that the detention of enemy
combatants in the context of a non-international armed conflict ‘would normally amount to arbitrary detention as
other effective measures addressing the threat, including the criminal justice system, would be available.’ On the
contrary, in both international and non-international armed conflicts, a State may detain enemy combatants
consistent with the law of armed conflict until the end of hostilities. Similarly, to the extent paragraphs 15 and 66
are intended to address law-of-war detention in situations of armed conflict, it would be incorrect to state that there
is a ‘right to take proceedings before a court to enable the court to decide without delay on the lawfulness of
detention’ in all cases. In addition, to the extent the discussion of an individual right to compensation under Article
9 in paragraphs 49-52 is intended to extend to individuals detained in the context of an armed conflict, as a matter of
international law, the rules governing available remedies for unlawful detention in the context of an armed conflict
would be drawn from international humanitarian law.”).
93 Coard, et al. v. United States, Inter-American Commission on Human Rights, Organization of American States,
Case 10.951, Report 109/99, ¶42 (Sept. 29, 1999) (“[I]n a situation of armed conflict, the test for assessing the
observance of a particular right, such as the right to liberty, may, under given circumstances, be distinct from that
applicable in a time of peace. For that reason, the standard to be applied must be deduced by reference to the
applicable lex specialis.”); Juan Carlos Abella v. Argentina, Inter-American Commission on Human Rights,
Organization of American States, Case 11.137, OEA/Ser.L/V/II.98, ¶161 (Nov. 18, 1997) (“[T]he Commission must
necessarily look to and apply definitional standards and relevant rules of humanitarian law as sources of
authoritative guidance in its resolution of this and other kinds of claims alleging violations of the American
Convention in combat situations.”); Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 1996
I.C.J. 226, 240 (¶25) (“In principle, the right not arbitrarily to be deprived of one’s life applies also in hostilities.
The test of what is an arbitrary deprivation of life, however, then falls to be determined by the applicable lex
specialis, namely, the law applicable to armed conflict which is designed to regulate the conduct of hostilities.”).
23
ensuring the right and opportunity of every citizen to vote and to be elected at genuine periodic
elections.94
1.6.3.2 Different Views on the Applicability of Human Rights Treaties. In
conducting operations with coalition partners, it may be important to consider that some States
may have different perspectives on the applicability of human rights treaties. Such differences
may result from different legal interpretations or from the fact that the other State is a Party to
different human rights treaties than the United States. For example, the European Court of
Human Rights - as well as some European States - have construed certain obligations under the
European Convention on Human Rights (ECHR) as applicable to their military forces abroad
during occupation.95
1.6.3.3 International Covenant on Civil and Political Rights (ICCPR). The
United States is a Party to the International Covenant on Civil and Political Rights (ICCPR).
The ICCPR creates obligations for a State with respect to persons within its territory and
subject to its jurisdiction.96 The United States has long interpreted the ICCPR not to apply
abroad.97 The inclusion of the reference to “within its territory” in Article 2(1) of the ICCPR
was adopted as a result of a proposal made by U.S. delegate Eleanor Roosevelt - specifically to
94 Fourth Periodic Report of the United States of America to the United Nations Committee on Human Rights
Concerning the International Covenant on Civil and Political Rights, Dec. 30, 2011, ¶506 (“With respect to the
application of the Covenant and the international law of armed conflict (also referred to as international
humanitarian law or ‘IHL’), the United States has not taken the position that the Covenant does not apply ‘in time of
war.’ Indeed, a time of war does not suspend the operation of the Covenant to matters within its scope of
application. To cite but two obvious examples from among many, a State Party’s participation in a war would in no
way excuse it from respecting and ensuring rights to have or adopt a religion or belief of one’s choice or the right
and opportunity of every citizen to vote and to be elected at genuine periodic elections.”).
95 Case of Al-Skeini and Others v. The United Kingdom, ECtHR, 55721/07, ¶149 (Jul. 7, 2011) (“It can be seen,
therefore, that following the removal from power of the Ba’ath regime and until the accession of the Interim
Government, the United Kingdom (together with the United States) assumed in Iraq the exercise of some of the
public powers normally to be exercised by a sovereign government. In particular the United Kingdom assumed
authority and responsibility for the maintenance of security in South East Iraq. In these exceptional circumstances
the Court considers that the United Kingdom, through its soldiers engaged in security operations in Basrah during
the period in question, exercised authority and control over individuals killed in the course of such security
operations so as to establish a jurisdictional link between the deceased and the United Kingdom for the purposes of
Article 1 of the (ECHR).”).
96 International Covenant on Civil and Political Rights, art. 2(1), Dec. 19, 1966, 999 UNTS 171, 173 (“Each State
Party to the present Covenant undertakes to respect and to ensure to all individuals within its territory and subject to
its jurisdiction the rights recognized in the present Covenant, without distinction of any kind, such as race, colour,
sex, language, religion, political or other opinion, national or social origin, property, birth or other status.”).
97 See, e.g., U.N. Human Rights Committee, Summary Record of the 1405th Meeting, U.N. Doc. CCPR/C/SR.1405
6-7 (¶20) (Apr. 24, 1995) (“Klein had asked whether the United States took the view that the Covenant did not apply
to government actions outside the United States. The Covenant was not regarded as having extraterritorial
application. In general, where the scope of application of a treaty was not specified, it was presumed to apply only
within a party’s territory. Article 2 of the Covenant expressly stated that each State party undertook to respect and
ensure the rights recognized ‘to all individuals within its territory and subject to its jurisdiction’. That dual
requirement restricted the scope of the Covenant to persons under United States jurisdiction and within United
States territory. During the negotiating history, the words ‘within its territory’ had been debated and were added by
vote, with the clear understanding that such wording would limit the obligations to within a Party’s territory.”).
24
ensure that a State Party’s obligations would not apply to persons outside its territories, such as
in occupied territory and leased territory.98
1.6.3.4 Convention Against Torture. The United States is a Party to the
Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment.99
The Convention against Torture was not intended to supersede the prohibitions against
torture already contained in customary international law and the 1949 Geneva Conventions or its
Additional Protocols.100 The law of war is the controlling body of law with respect to the
conduct of hostilities and the protection of war victims. Nevertheless, a time of war does not
suspend operation of the Convention Against Torture. The Convention Against Torture
continues to apply even when a State is engaged in armed conflict.101 For example, a state of
war could not justify a State’s torture of individuals during armed conflict.102
In addition, where the text of the Convention Against Torture provides that obligations
apply to a State Party in “any territory under its jurisdiction,” such obligations, including the
obligations in Articles 2 and 16 to prevent torture and cruel, inhuman, or degrading treatment or
punishment, extend to certain areas beyond the sovereign territory of the State Party, and more
specifically to “all places that the State Party controls as a governmental authority.”103
1.6.4 Just War Tradition. The Just War Tradition describes customs, ethical codes, and
moral teachings associated with warfare that military thinkers and philosophers have developed
over centuries to seek the moral justification of and the limitations to war.104
98 Refer to § 11.1.2.6 (Occupation and the ICCPR and Other Human Rights Treaties).
99 Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, Dec. 10, 1984,
1465 UNTS 85.
100 Refer to § 8.2.1 (Protection Against Violence, Torture, and Cruel Treatment).
101 Mary McLeod, Acting Legal Adviser, Department of State, Opening Statement at 53rd Session of the U.N.
Committee Against Torture, Nov. 3 - 28, 2014, Nov. 12, 2014 (“Although the law of armed conflict is the
controlling body of law with respect to the conduct of hostilities and the protection of war victims, a time of war
does not suspend operation of the Convention Against Torture, which continues to apply even when a State is
engaged in armed conflict. The obligations to prevent torture and cruel, inhuman, and degrading treatment and
punishment in the Convention remain applicable in times of armed conflict and are reinforced by complementary
prohibitions in the law of armed conflict.”).
102 Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, art. 2(2), Dec. 10,
1984, 1465 UNTS 85, 114 (“No exceptional circumstances whatsoever, whether a state of war or a threat of war,
internal political instability or any other public emergency, may be invoked as a justification of torture.”).
103 Mary McLeod, Acting Legal Adviser, Department of State, Opening Statement at 53rd Session of the U.N.
Committee Against Torture, Nov. 3 - 28, 2014, Nov. 12, 2014 (“In brief, we understand that where the text of the
Convention provides that obligations apply to a State Party in ‘any territory under its jurisdiction,’ such obligations,
including the obligations in Articles 2 and 16 to prevent torture and cruel, inhuman or degrading treatment or
punishment, extend to certain areas beyond the sovereign territory of the State Party, and more specifically to ‘all
places that the State Party controls as a governmental authority.’ We have determined that the United States
currently exercises such control at the U.S. Naval Station at Guantanamo Bay, Cuba, and with respect to U.S.
registered ships and aircraft.”).
104 WILLIAM O’BRIEN, THE CONDUCT OF JUST AND LIMITED WAR 4 (1981) (“The just-war tradition begins with the
efforts of St. Augustine to justify Christian participation in Roman wars. From this foundation, St. Thomas Aquinas
25
The Just War Tradition provides part of the philosophical foundation for the modern law
of war and has considered both jus ad bellum and jus in bello. The Just War Tradition developed
criteria or principles that have provided the foundation for modern jus ad bellum rules.105
Similarly, law of war treaties that provide jus in bello rules, such as the 1949 Geneva
Conventions, are also rooted in the Just War Tradition. The Just War Tradition remains relevant
for decisions to employ U.S. military forces and in warfighting.106
1.6.5 Rules of Engagement (ROE). Rules of engagement (ROE) have been defined as
“[d]irectives issued by competent military authority that delineate the circumstances and
limitations under which United States forces will initiate and/or continue combat engagement
with other forces encountered.”107 ROE are used by States to tailor the rules for the use of force
to the circumstances of a particular operation.108
ROE reflect legal, policy, and operational considerations, and are consistent with the
international law obligations of the United States, including the law of war.109 ROE may restrict
and other Scholastic thinkers developed the Scholastic just-war doctrine. This doctrine reached its mature form by
the time of the writings of Vitoria and Suarez in the sixteenth and seventeenth centuries. Various Protestant
moralists and secular writers dealt with just-war issues during the Reformation, but by the eighteenth century just-
war doctrine was becoming a curiosity that was not taken seriously. It remained for the twentieth century reaction
against total war to spark renewed studies in the just-war tradition.”).
105 Refer to § 1.11.1 (Jus ad Bellum Criteria).
106 See, e.g., Barack Obama, Remarks on Accepting the Nobel Peace Prize in Oslo, Dec. 10, 2009, 2009-II PUBLIC
PAPERS OF THE PRESIDENTS 1799 (“And over time, as codes of law sought to control violence within groups, so did
philosophers and clerics and statesmen seek to regulate the destructive power of war. The concept of a just war
emerged, suggesting that war is justified only when certain conditions were met: if it is waged as a last resort or in
self-defense; if the force used is proportional; and if, whenever possible, civilians are spared from violence.”);
George H. W. Bush, Remarks at the Annual Convention of the National Religious Broadcasters, Jan. 28, 1991,
1991-I PUBLIC PAPERS OF THE PRESIDENTS 70 (“Nowhere is this more true than in the Persian Gulf where -- despite
protestations of Saddam Hussein -- it is not Iraq against the United States, it’s the regime of Saddam Hussein against
the rest of the world. Saddam tried to cast this conflict as a religious war, but it has nothing to do with religion per
se. It has, on the other hand, everything to do with what religion embodies: good versus evil, right versus wrong,
human dignity and freedom versus tyranny and oppression. The war in the Gulf is not a Christian war, a Jewish
war, or a Moslem war; it is a just war. And it is a war with which good will prevail.”).
107 JOINT PUBLICATION 1-04, Legal Support to Military Operations, GL-3 (Aug. 17, 2011) (“rules of engagement.
Directives issued by competent military authority that delineate the circumstances and limitations under which
United States forces will initiate and/or continue combat engagement with other forces encountered. Also called
ROE.”).
108 For example, Juan Carlos Gomez, Twenty-First-Century Challenges: The Use of Military Forces to Combat
Criminal Threats, 88 INTERNATIONAL LAW STUDIES 279, 285-86 (2012) (“There must be clear, understandable rules
provided to military forces on the circumstances under which force may be used and the type and degree of that
force. This is dependent on the mission assigned to the forces. In Colombia, two differently colored cards are used.
A blue card is used when the military unit is engaged in a law enforcement mission. The rules on the blue card are
based on HRL. They provide for the use of force only when no other option is available to accomplish the mission
and in self-defense of the person and others. The red card is used in operations against military objectives. These
cards are based on IHL and permit the offensive use of force, including lethal force if demanded by military
necessity.”).
109 J. Fred Buzhardt, DoD General Counsel, Letter to Senator Edward Kennedy, Sept. 22, 1972, reprinted in 67 AJIL
124 (1973) (“With reference to your inquiry concerning the rules of engagement governing American military
activity in Indochina, you are advised that rules of engagement are directives issued by competent military authority
26
actions that would be lawful under the law of war, but may not permit actions prohibited by the
law of war. States have used ROE as part of the implementation of their law of war obligations
during military operations.110
1.6.6 Code of Conduct for U.S. Armed Forces. The Code of Conduct is a moral guide for
U.S. forces to govern their conduct in resisting capture and their actions in the event they fall
into hostile hands.111 The Code of Conduct was developed after the Korean War and was
promulgated by Executive Order.112 The Code of Conduct is consistent with the law of war
obligations of the United States, including obligations in the GPW.113
1.7 TREATIES
Treaties are generally defined as international agreements concluded between States in
written form and governed by international law.114 Under international law, a treaty is binding
upon States that are Parties to it.115
The United States is a Party to a number of law of war treaties.116 For many years, the
Department of State has published annually a listing of treaties and other international
agreements in force for the United States. This publication has provided helpful information
about such treaties, including the date of U.S. ratification and a listing of other Parties to each
treaty.
1.7.1 Treaties - Notes on Terminology. Treaties may be titled or referred to by several
other terms in addition to “treaty” - including convention, protocol, or agreement. In the context
of the law of war, “protocol” often refers to an agreement that supplements or updates an
existing agreement.
1.7.1.1 “Treaties” Under U.S. Constitutional Law. Under the Constitution, a
“treaty” must receive the advice and consent of the Senate before U.S. ratification or accession.
Certain international agreements, such as Executive agreements, are not classified as “treaties”
which delineate the circumstances and limitations under which United States Forces will initiate and/or continue
combat engagement with the enemy. These rules are the subject of constant review and command emphasis. They
are changed from time to time to conform to changing situations and the demands of military necessity. One critical
and unchanging factor is their conformity to existing international law as reflected in the Hague Conventions of
1907 and the Geneva Conventions of 1949, as well as with the principles of customary international law of which
UNGA Resolution 2444 (XXIII) is deemed to be a correct restatement.”).
110 Refer to § 5.1.2 (Adherence to Law of War Obligations in the Conduct of Hostilities During Military Operations).
111 Refer to § 9.39 (Code of Conduct for U.S. Armed Forces).
112 Refer to § 9.39.2 (Background on the U.S. Code of Conduct).
113 Refer to § 9.39.1 (Text of the Code of Conduct and Discussion).
114 Consider, e.g., VCLT art. 1(a) (“‘[T]reaty’ means an international agreement concluded between States in written
form and governed by international law, whether embodied in a single instrument or in two or more related
instruments and whatever its particular designation;”).
115 Refer to § 1.10.1.1 (Legal Force of Treaties Among States).
116 Refer to § 19.2.1 (Law of War Treaties to Which the United States Is a Party).
27
for the purposes of this requirement, although they may be characterized as “treaties” for the
purposes of international law and impose obligations upon the United States.117
1.7.2 Reservations to Treaties. A State may limit the application of provisions of a treaty
by reservation upon ratification of the treaty as long as the treaty does not prohibit such
reservations and the reservation is compatible with the object and purpose of the treaty.118 For
example, the United States has taken a reservation to certain provisions of CCW Protocol III on
Incendiary Weapons.119 On the other hand, for example, the Chemical Weapons Convention
expressly prohibits reservations to the Convention and prohibits reservations to the Convention’s
Annexes that are incompatible with its object and purpose.120
1.7.3 Withdrawal From Treaties. Under certain circumstances, States may withdraw
from treaties.121 Some law of war and arms control treaties specify the conditions under which
Parties may withdraw from them.122 Even upon denunciation of a treaty, States remain bound by
customary international law, including law of war principles.123
1.7.4 Use of Certain Subsequent Practice in Treaty Interpretation. Certain subsequent
State practice in the application of a treaty provision may be taken into account when
interpreting that provision.124 Subsequent State practice is important as an element of
117 See, e.g., Weinberger v. Rossi, 456 U.S. 25, 29-30 (1982) (“The word ‘treaty’ has more than one meaning.
Under principles of international law, the word ordinarily refers to an international agreement concluded between
sovereigns, regardless of the manner in which the agreement is brought into force. Under the United States
Constitution, of course, the word ‘treaty’ has a far more restrictive meaning. Article II, §2, cl. 2, of that instrument
provides that the President ‘shall have Power, by and with the Advice and Consent of the Senate, to make Treaties,
provided two thirds of the Senators present concur.’”) (internal citation omitted).
118 Consider VCLT art. 19 (“A State may, when signing, ratifying, accepting, approving or acceding to a treaty,
formulate a reservation unless: (a) the reservation is prohibited by the treaty; (b) the treaty provides that only
specified reservations, which do not include the reservation in question, may be made; or (c) in cases not failing
under subparagraphs (a) and (b), the reservation is incompatible with the object and purpose of the treaty.”). See
also William P. Rogers, Letter of Submittal, Oct. 18, 1971, MESSAGE FROM THE PRESIDENT TRANSMITTING THE
VCLT 2 (“Part 2 of Section II sets forth the rules on reservations to treaties (Articles 19-23). The articles reflect
flexible current treaty practice with regard to multilateral treaties as generally followed since World War II. The
earlier traditional rule on reservations had been that in order for a State to become party to a multilateral treaty with
a reservation the unanimous consent of the other parties was required. That rule has given way in practice to a more
flexible approach particularly after the International Court of Justice in 1951 handed down its Advisory Opinion on
Reservations to the Genocide Convention.”).
119 Refer to § 6.14.3.2 (U.S. Reservation to CCW Protocol III on Incendiary Weapons).
120 Refer to § 19.22 (Chemical Weapons Convention).
121 Consider VCLT art. 54 (“The termination of a treaty or the withdrawal of a party may take place: (a) in
conformity with the provisions of the treaty; or (b) at any time by consent of all the parties after consultation with
the other contracting States.”).
122 See, e.g., CCW art. 9(1) (“Any High Contracting Party may denounce this Convention or any of its annexed
Protocols by so notifying the Depositary.”); GWS art. 63 (“Each of the High Contracting Parties shall be at liberty to
denounce the present Convention.”).
123 Refer to § 19.8.3 (Martens Clause).
124 Consider VCLT art. 31(3) (“There shall be taken into account, together with the context: (b) Any subsequent
practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation;”).
See also I RESTATEMENT (THIRD) OF FOREIGN RELATIONS LAW OF THE UNITED STATES 199 (§325(2)) (1987) (“Any
28
interpretation when it constitutes objective evidence of the understanding of the Parties as to the
meaning of the treaty.125 For example, the subsequent practice of States in the application of the
GWS-Sea’s requirements for hospital ships has clarified that States may use hospital ships with
the capability to conduct encrypted communications.126
1.7.5 Treaties and Domestic Implementing Legislation. States may enact domestic
legislation to implement treaty provisions. Although such implementing legislation is not
international law, it may reflect a State’s interpretation of those provisions.127
A State’s domestic implementing legislation, or lack of such legislation, however, does
not justify that State’s noncompliance with an international obligation as a matter of international
law.128
1.8 CUSTOMARY INTERNATIONAL LAW
Customary international law results from a general and consistent practice of States that
is followed by them from a sense of legal obligation (opinio juris).129 Customary international
law is an unwritten form of law in the sense that it is not created through a written agreement by
States.
subsequent agreement between the parties regarding the interpretation of the agreement, and subsequent practice
between the parties in the application of the agreement, are to be taken into account in its interpretation.”); I
RESTATEMENT (THIRD) OF FOREIGN RELATIONS LAW OF THE UNITED STATES 203 (§325, comment c) (1987) (This
“conforms to United States modes of interpretation, affirming that subsequent practice of the parties can be taken
into account in interpreting international agreements.”).
125 See II YEARBOOK OF THE INTERNATIONAL LAW COMMISSION 221 (¶15) (1966) (“The importance of such
subsequent practice in the application of the treaty, as an element of interpretation, is obvious; for it constitutes
objective evidence of the understanding of the parties as to the meaning of the treaty. Recourse to it as a means of
interpretation is well-established in the jurisprudence of international tribunals.”). See also Case Concerning
Kasikili/Sedudu Island (Botswana v. Namibia), Judgment, 1999 I.C.J. 1045, 1075-76 (¶49) (same); Russian Claim
for Interest on Indemnities (The Russian Indemnity Case), Russia/Turkey, 11 R.I.A.A. 421, 433 (1912) Permanent
Court of Arbitration Unofficial English Translation, 3 (“Whereas the fulfilment of obligations is, between States as
between individuals, the surest commentary on the meaning of these obligations;”); Case Concerning The Temple of
Preah Vihear (Cambodia v. Thailand), Merits, Judgment, 1962 I.C.J. 6, 34 (The map “was accepted by the Parties in
1908 and thereafter as constituting the result of the interpretation given by the two Governments to the delimitation
which the Treaty itself required. In other words, the Parties at that time adopted an interpretation of the treaty
settlement which caused the map line, in so far as it may have departed from the line of the watershed, to prevail
over the relevant clause of the treaty.”).
126 Refer to § 7.12.2.7 (Use of Secret Codes for Communication).
127 See United States v. Navarre, 173 U.S. 77, 79 (1899) (noting that “[i]f the meaning of the treaty was doubtful, it
was competent for Congress to resolve the doubt” in its enactment of legislation).
128 Refer to § 1.10.1.4 (Force of International Law Notwithstanding a State’s Domestic Law).
129 See I RESTATEMENT (THIRD) OF FOREIGN RELATIONS LAW OF THE UNITED STATES 24 (§102(2)) (1987)
(“Customary international law results from a general and consistent practice of states followed by them from a sense
of legal obligation.”).
29
Customary international law is generally binding on all States, but States that have been
persistent objectors to a customary international law rule during its development are not bound
by that rule.130
Assessing whether State practice and opinio juris have resulted in a rule of customary
international law may be a difficult inquiry.131
1.8.1 Relationship Between Treaties and Customary International Law. Treaty
provisions may, inter alia: (1) not reflect customary international law; (2) reflect customary
international law; or (3) be based on customary law, but not precisely reflect it.
In most cases, treaty provisions do not reflect customary international law. For example,
AP I’s provisions changing which persons would be entitled to the privileges of combatant status
were viewed as novel at the time of the adoption of AP I and as not reflecting customary
international law.132
In some cases, a treaty provision may reflect customary international law. The rule
reflected in the treaty would thus be understood to be binding, even if the treaty provision was
not applicable, because the rule maintains a separate existence as a customary norm.133 For
example, provisions of Hague IV and the Hague IV Regulations have been found to reflect
customary international law.134 Law of war treaties have specified that customary law and
principles continue to apply even if the treaty is not applicable.135
A treaty provision may be based on an underlying principle that is an accepted part of
customary law, but the precise language of the treaty provision may not reflect customary
international law because there may be considerable disagreement as to the precise statement of
130 Refer to § 1.10.1.2 (Legal Force of Customary International Law Among States).
131 Michael J. Matheson, Deputy Legal Adviser, Department of State, Remarks on the United States Position on the
Relation of Customary International Law to the 1977 Protocols Additional to the 1949 Geneva Conventions at the
Sixth Annual American Red Cross-Washington College of Law Conference on International Humanitarian Law
(Jan. 22, 1987), 2 AMERICAN UNIVERSITY JOURNAL OF INTERNATIONAL LAW AND POLICY 419, 421-22 (1987)
(“Having described the reasons why I believe that the topic of this Workshop is important and very relevant to
decisions currently being taken with respect to Protocol I in the United States and other governments, it is of course
much more difficult to say exactly which of the rules contained in the Protocol currently are in fact a part of
customary law. As I am sure you all appreciate quite well, there is no clear line drawn in the dust for all to see
between those principles that are now customary law and those which have not yet attained the degree of acceptance
and observance that might make them customary law. Instead, there are degrees of acceptance and degrees of
observance, and the judgment as to what degree of each is sufficient for establishment as customary law is
inherently subjective and hard to define precisely.”).
132 Refer to, e.g., § 4.6.1.2 (AP I and the GPW 4A(2) Conditions).
133 Military and Paramilitary Activities in and Against Nicaragua (Nicaragua v. United States), Merits, Judgment,
1986 I.C.J. 14, 95 (¶178) (“[E]ven if two norms belonging to two sources of international law appear identical in
content, and even if the States in question are bound by these rules both on the level of treaty-law and on that of
customary international law, these norms retain a separate existence.”).
134 Refer to § 19.8.2.1 (Hague IV and Customary International Law).
135 Refer to § 19.8.3 (Martens Clause).
30
that underlying principle.136 For example, the United States has expressed support for the
customary principle on which Article 51(3) of AP I is based, but has noted that Article 51(3) of
AP I, as drafted, does not reflect customary international law.137
1.8.2 State Practice. One part of determining whether a purported rule is customary
international law is to analyze whether there is a general and consistent practice of States that
supports the purported rule.
An analysis of State practice to determine whether a purported rule reflects the customary
international law of war should include consideration of, inter alia: (1) whether the State
practice is extensive and virtually uniform; (2) actual operational practice; (3) the practice of
specially affected States; and (4) contrary practice.
1.8.2.1 Extensive and Virtually Uniform. State practice should be sufficiently
dense and consistent to meet the “extensive and virtually uniform” standard generally required
for existence of a customary rule.138
1.8.2.2 Actual Operational Practice. An analysis of State practice should include
an analysis of actual operational practice by States during armed conflict. Although manuals or
other official statements may provide important indications of State behavior, they cannot
replace a meaningful assessment of operational State practice.139
136 Michael J. Matheson, Deputy Legal Adviser, Department of State, Remarks on the United States Position on the
Relation of Customary International Law to the 1977 Protocols Additional to the 1949 Geneva Conventions at the
Sixth Annual American Red Cross-Washington College of Law Conference on International Humanitarian Law
(Jan. 22, 1987), 2 AMERICAN UNIVERSITY JOURNAL OF INTERNATIONAL LAW AND POLICY 419, 422 (1987) (“In
addition, it may be possible in many cases to say that a general principle is an accepted part of customary law, but to
have considerable disagreement as to the precise statement of that general principle.”).
137 Refer to § 5.9.1.2 (AP I, Article 51(3) Provision on Direct Participation in Hostilities).
138 See, e.g., Harold Koh, Legal Adviser, Department of State, Responses to Questions Submitted by Senator Richard
G. Lugar, in Libya and War Powers: Hearing Before the Committee on Foreign Relations, U.S. Senate, 112th
Congress, First Session, 53, 57 (Jun. 28, 2011) (“Determining that a principle has become customary international
law requires a rigorous legal analysis to determine whether such principle is supported by a general and consistent
practice of states followed by them from a sense of legal obligation. Although there is no precise formula to indicate
how widespread a practice must be, one frequently used standard is that state practice must be extensive and
virtually uniform, including among States particularly involved in the relevant activity (i.e., specially affected
States).”); North Sea Continental Shelf Cases (Federal Republic of Germany v. Denmark; Federal Republic of
Germany v. Netherlands), 1969 I.C.J. 3, 43 (¶74) (“Although the passage of only a short period of time is not
necessarily, or of itself, a bar to the formation of a new rule of customary international law on the basis of what was
originally a purely conventional rule, an indispensable requirement would be that within the period in question, short
though it might be, State practice, including that of States whose interests are specially affected, should have been
both extensive and virtually uniform in the sense of the provision invoked; and should moreover have occurred in
such a way as to show a general recognition that a rule of law or legal obligation is involved.”).
139 U.S. RESPONSE TO ICRC CIHL STUDY 515 (“Second, we are troubled by the type of practice on which the Study
has, in too many places, relied. Our initial review of the State practice volumes suggests that the Study places too
much emphasis on written materials, such as military manuals and other guidelines published by States, as opposed
to actual operational practice by States during armed conflict. Although manuals may provide important indications
of State behavior and opinio juris, they cannot be a replacement for a meaningful assessment of operational State
practice in connection with actual military operations. We also are troubled by the extent to which the Study relies
31
1.8.2.3 Specially Affected States. The practice of “States whose interests are
specially affected,” e.g., States with a distinctive history of participation in the relevant matter,
must support the purported rule.140 States that have had a wealth of experience, or that have
otherwise had significant opportunities to develop a carefully considered military doctrine, may
be expected to have contributed a greater quantity and quality of State practice relevant to the
law of war than States that have not.
For example, “specially affected States” could include, depending upon the relevant
matter, the nuclear powers, other major military powers, and occupying or occupied States.141
As a case in point, the United Kingdom has been viewed as a specially affected State with
respect to the law of the sea.142
1.8.2.4 Contrary Practice. Evidence of contrary practice, i.e., the practice of
States that does not support the purported rule, must be considered in assessing whether that rule
exists as a rule of customary international law.143
on non-binding resolutions of the General Assembly, given that States may lend their support to a particular
resolution, or determine not to break consensus in regard to such a resolution, for reasons having nothing to do with
a belief that the propositions in it reflect customary international law.”).
140 See U.S. RESPONSE TO ICRC CIHL STUDY 517 endnote 3 (“Not every State that has participated in an armed
conflict is ‘specially affected;’ such States do generate salient practice, but it is those States that have a distinctive
history of participation that merit being regarded as ‘specially affected.’”); Written Statement of the Government of
the United States of America, 28-29, Jun. 20, 1995, I.C.J., Request by the United Nations General Assembly for an
Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons (“Evidence of a customary norm
requires indication of ‘extensive and virtually uniform’ State practice, including States whose interests are ‘specially
affected.’ … With respect to the use of nuclear weapons, customary law could not be created over the objection of
the nuclear-weapon States, which are the States whose interests are most specially affected.”).
141 Theodor Meron, The Continuing Role of Custom in the Formation of International Humanitarian Law, 90 AJIL
238, 249 (1996) (“A broader question, however, concerns the degree of weight to be assigned to the practice of
various states in the formation of the international customary law of war. I find it difficult to accept the view,
sometimes advanced, that all states, whatever their geographical situation, military power and interests, inter alia,
have an equal role in this regard. Belligerency is only one factor here. The practice and opinion of Switzerland, for
example, as a neutral state, surely have more to teach us about assessment of customary neutrality law than the
practice of states that are not committed to the policy of neutrality and have not engaged in pertinent national
practice. The practice of ‘specially affected states’ -such as nuclear powers, other major military powers, and
occupying and occupied states-which have a track record of statements, practice and policy, remains particularly
telling. I do not mean to denigrate state equality, but simply to recognize the greater involvement of some states in
the development of the law of war, not only through operational practice but through policies expressed, for
example, in military manuals.”).
142 See, e g., The Paquete Habana, 175 U.S. 677, 719 (1900) (Fuller, J., dissenting) (noting that “[i]t is difficult to
conceive of a law of the sea of universal obligation to which Great Britain has not acceded.”).
143 For example, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 1996 I.C.J. 311, 311-12
(Dissenting Opinion of Vice-President Schwebel) (“One way of surmounting the antinomy between practice and
principle would be to put aside practice. That is what those who maintain that the threat or use of nuclear weapons
is unlawful in all circumstances do. … State practice demonstrates that nuclear weapons have been manufactured
and deployed by States for some 50 years; that in that deployment inheres a threat of possible use; and that the
international community, by treaty and through action of the United Nations Security Council, has, far from
proscribing the threat or use of nuclear weapons in all circumstances, recognized in effect or in terms that in certain
circumstances nuclear weapons may be used or their use threatened.”).
32
In addition, the persistent objection of States may be relevant after the formation of that
rule by preventing the application of that rule to States that have objected to that rule during its
development.144
1.8.3 Opinio Juris. In addition to analyzing State practice, one must determine whether
the State practice results from a sense of legal obligation (opinio juris) or merely reflects States’
policy or practical interests. Opinio juris cannot simply be inferred from consistent State
practice, which may exist for reasons other than opinio juris.145 For example, the fact that
nuclear weapons have not been used to conduct attacks during armed conflict since 1945 does
not reflect a prohibition in customary international law against their use because such lack of use
has not resulted from opinio juris.146
1.8.3.1 Potential Sources of Opinio Juris. It may be difficult to find evidence of
opinio juris, and care should be exercised in assessing whether a source reflects opinio juris on
the part of a State. For example, treaty provisions do not necessarily reflect opinio juris.147
Similarly, rather than indicating a position expressed out of a sense of a customary legal
obligation, a State’s military manual often recites requirements applicable to that State under
treaties to which it is a Party, or provides guidance to its military forces for reasons of national
policy.148
144 Refer to § 1.8.4 (Objection During Development).
145 U.S. RESPONSE TO ICRC CIHL STUDY 515 (“Although the same action may serve as evidence both of State
practice and opinio juris, we do not agree that opinio juris simply can be inferred from practice. Both elements
instead must be assessed separately in order to determine the presence of a norm of customary international law.”).
146 See Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 1996 I.C.J. 226, 253-54 (¶¶65-67)
(“States which hold the view that the use of nuclear weapons is illegal have endeavoured to demonstrate the
existence of a customary rule prohibiting this use. They refer to a consistent practice of non-utilization of nuclear
weapons by States since 1945 and they would see in that practice the expression of an opinio juris on the part of
those who possess such weapons. Some other States, which assert the legality of the threat and use of nuclear
weapons in certain circumstances, invoked the doctrine and practice of deterrence in support of their argument.
They recall that they have always, in concert with certain other States, reserved the right to use those weapons in the
exercise of the right to self-defence against an armed attack threatening their vital security interests. In their view, if
nuclear weapons have not been used since 1945, it is not on account of an existing or nascent custom but merely
because circumstances that might justify their use have fortunately not arisen. The Court does not intend to
pronounce here upon the practice known as the ‘policy of deterrence.’ It notes that it is a fact that a number of
States adhered to that practice during the greater part of the Cold War and continue to adhere to it. Furthermore, the
members of the international community are profoundly divided on the matter of whether non-recourse to nuclear
weapons over the past 50 years constitutes the expression of an opinio juris. Under these circumstances the Court
does not consider itself able to find that there is such an opinio juris.”).
147 U.S. RESPONSE TO ICRC CIHL STUDY 515 (“One therefore must be cautious in drawing conclusions as to opinio
juris from the practice of States that are parties to conventions, since their actions often are taken pursuant to their
treaty obligations, particularly inter se, and not in contemplation of independently binding customary international
law norms.”).
148 U.S. RESPONSE TO ICRC CIHL STUDY 516 (“We are troubled by the Study’s heavy reliance on military manuals.
We do not agree that opinio juris has been established when the evidence of a State’s sense of legal obligation
consists predominately of military manuals. Rather than indicating a position expressed out of a sense of a
customary legal obligation, in the sense pertinent to customary international law, a State’s military manual often
(properly) will recite requirements applicable to that State under treaties to which it is a party. Reliance on
33
1.8.4 Objection During Development. Even if a rule otherwise reflects customary
international law, the rule is not binding upon a State that has persistently objected to that rule
during its development.149 This principle is an accepted application of the traditional principle
that international law essentially depends on the consent of States.150
1.9 SUBSIDIARY MEANS OF DETERMINING INTERNATIONAL LAW
As a subsidiary means, it may be helpful to consult judicial decisions and the teachings of
the most highly qualified publicists of various nations in determining the applicable rules of
international law. These means are subsidiary in the sense that they do not, in themselves,
constitute sources of treaty or customary international law.
Discretion must be exercised in weighing sources, however, because sources vary
significantly in their probative value. For example, the United States has said that it is not in a
position to accept without further analysis the conclusions in a study on customary international
humanitarian law published by the ICRC.151
1.9.1 Judicial Decisions. Judicial decisions have sometimes been used as a subsidiary
means of determining the rules of international law.152
Judicial decisions are generally consulted as only persuasive authority because a
judgment rendered by an international court generally binds only the parties to the case in respect
provisions of military manuals designed to implement treaty rules provides only weak evidence that those treaty
rules apply as a matter of customary international law in non-treaty contexts.”).
149 See Fisheries Case, (United Kingdom v. Norway), Judgment, 1951 I.C.J. 116, 131 (“In these circumstances the
Court deems it necessary to point out that although the ten-mile rule has been adopted by certain States both in their
national law and in their treaties and conventions, and although certain arbitral decisions have applied it as between
these States, other States have adopted a different limit. Consequently, the ten-mile rule has not acquired the
authority of a general rule of international law. In any event the ten-mile rule would appear to be inapplicable as
against Norway inasmuch as she has always opposed any attempt to apply it to the Norwegian coast.”); Asylum
Case (Colombia v. Peru), 1950 I.C.J. 266, 277-78 (“The Court cannot therefore find that the Colombian Government
has proved the existence of such a custom. But even if it could be supposed that such a custom existed between
certain Latin-American States only, it could not be invoked against Peru which, far from having by its attitude
adhered to it, has, on the contrary, repudiated it by refraining from ratifying the Montevideo Conventions of 1933
and 1939, which were the first to include a rule concerning the qualification of the offence in matters of diplomatic
asylum.”). See also U.S. RESPONSE TO ICRC CIHL STUDY 529 endnote 38 (“We note that the Study raises doubts
about the continued validity of the ‘persistent objector’ doctrine. Study, Vol. I, p. xxxix. The U.S. Government
believes that the doctrine remains valid.”).
150 I RESTATEMENT (THIRD) OF THE FOREIGN RELATIONS LAW OF THE UNITED STATES 32 (§102, Reporters’ Note 2)
(1987) (“That a rule of customary law is not binding on any state indicating its dissent during the development of the
rule (Comment d) is an accepted application of the traditional principle that international law essentially depends on
the consent of states.”).
151 Refer to § 19.25 (2005 ICRC Study on Customary International Humanitarian Law).
152 ICJ STATUTE art. 38(1) (“The Court, whose function is to decide in accordance with international law such
disputes as are submitted to it, shall apply:
… d. subject to the provisions of Article 59, judicial decisions … as
subsidiary means for the determination of rules of law.”).
34
of that particular case.153 The legal reasoning underlying the decisions of the International Court
of Justice is not binding on States.154 Similarly, the decisions of the International Criminal
Tribunal for the Former Yugoslavia and the International Criminal Tribunal for Rwanda cannot,
as a strictly legal matter, “bind” other courts.155
The legal principle of stare decisis does not generally apply between international
tribunals, i.e., customary international law does not require that one international tribunal follow
the judicial precedent of another tribunal in dealing with questions of international law.156
Moreover, depending on the international tribunal, a tribunal may not be bound by its prior
decisions. Some international courts, however, may adhere to their own prior decisions in
resolving a case absent a sufficiently persuasive reason to reconsider the point of law.157
153 See, e.g., ICJ STATUTE art. 59 (“The decision of the Court has no binding force except between the parties and in
respect of that particular case.”).
154 John B. Bellinger, III, Department of State Legal Adviser, 2006 DIGEST OF UNITED STATES PRACTICE IN
INTERNATIONAL LAW 1024 (“We believe that these concerns were largely borne out in the advisory opinion
rendered by the Court. In practice, the opinion has made little meaningful contribution to efforts to resolve issues
between the Israelis and Palestinians. Also, the Court’s opinion is open to criticism on its treatment of both factual
and legal issues, in some cases due more to process than to any fault on the part of the Court. For example, the fact
that the General Assembly had already declared itself on many of the issues, risks creating the impression that the
Court was being used to advance a particular set of political claims. Also of concern are efforts in some quarters to
suggest that aspects of the Court’s advisory opinion, such as that relating to the extraterritorial application of the
International Covenant on Civil and Political Rights, have binding force on member states in contexts that go
beyond those addressed in the advisory opinion. This of course, is not the case. Under the ICJ statute, states are
bound only by the decisions—and not by the Court’s reasoning underlying those decisions—in contentious cases to
which they are parties, and advisory opinions have no binding force at all, but rather serve to provide guidance on
legal questions to the UN organ or specialized agency requesting them.”).
155 Harold Hongju Koh, Legal Adviser, Department of State, Remarks on international criminal justice at the Vera
Institute of Justice in New York and at Leiden University, Campus The Hague, 2012 DIGEST OF UNITED STATES
PRACTICE IN INTERNATIONAL LAW 61, 67 (“The ICTY and ICTR began developing a modern jurisprudence of
criminal liability that was based on existing law as applied to a modern ethnic conflict. One of the ICTY’s early
accomplishments was the Dusko Tadic case, which involved a relatively low-level offender who -- had he been
caught only a few years later -- would have been referred to Bosnia for domestic prosecution. The Tadic decision
provided a reasoned basis for the seminal conclusions that (1) the UN Security Council had the authority to set up a
criminal court under Chapter VII of the UN Charter; (2) the tribunal’s jurisdiction extended to war crimes
committed in the course of a non-international armed conflict; and (3) Tadic could be convicted for his association
with a small group of offenders, articulating the concept of joint criminal enterprise (“JCE”) that later became a
central feature of the ICTY’s work. … The post-WWII tribunals had largely ignored sexual violence, but the ICTY
and ICTR situated the issue within the existing law of war crimes, crimes against humanity, and genocide. Although
these decisions cannot, as a strictly legal matter ‘bind’ other courts, there is no doubt that the jurisprudence of the
ICTY and ICTR has been influential in the broader development of international criminal law.”).
156 I RESTATEMENT (THIRD) OF FOREIGN RELATIONS LAW OF THE UNITED STATES 36-37 (§103, comment b) (1987)
(“That provision [Article 59 of the Statute of the ICJ] reflects the traditional view that there is no stare decisis in
international law.”).
157 See, e.g., Prosecutor v. Aleksovski, ICTY Appeals Chamber, IT-95-14/1-A, Judgment, ¶¶107-109 (Mar. 24,
2000) (“[I]in the interests of certainty and predictability, the Appeals Chamber should follow its previous decisions,
but should be free to depart from them for cogent reasons in the interests of justice. … It is necessary to stress that
the normal rule is that previous decisions are to be followed, and departure from them is the exception. The Appeals
Chamber will only depart from a previous decision after the most careful consideration has been given to it, both as
to the law, including the authorities cited, and the facts.”).
35
1.9.2 Legal Writings of Highly Qualified Publicists. The writings “of the most highly
qualified publicists” have sometimes been used as a subsidiary means of determining the rules of
international law.158 For example, classical publicists, such as Hugo Grotius and Emmerich de
Vattel, and recognized scholars, such as Francis Lieber and Hersch Lauterpacht, have been
widely cited and relied upon as practitioners have sought to interpret and apply the law of war.
The standard for whose writings should be relied upon is high, and writings are only as
authoritative as the evidence upon which they are based. The writings should only be relied
upon to the degree they accurately reflect existing law, rather than the author’s views about what
the law should be.159
1.10 LEGAL FORCE OF THE LAW OF WAR
This section addresses the technical legal force of the law of war under international and
U.S. domestic law. As a matter of policy, DoD personnel may be required to adhere to law of
war rules, even where the rules do not technically apply as a matter of law.160
1.10.1 Legal Force of the Law of War Under International Law. The technical force of a
law of war rule depends on whether it takes the form of a treaty or customary international law.
1.10.1.1 Legal Force of Treaties Among States. Under international law, every
treaty in force is binding upon the Parties to it and must be performed by them in good faith.161
A treaty enters into force for a State after, inter alia, it has provided its consent to be bound by
the treaty.162 In some cases, the terms of a treaty may cause it to expire, and in other cases,
158 ICJ STATUTE art. 38(1) (“The Court, whose function is to decide in accordance with international law such
disputes as are submitted to it, shall apply: … d. subject to the provisions of Article 59, … the teachings of the most
highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.”).
159 See The Paquete Habana, 175 U.S. 677, 700 (1900) (“For this purpose, where there is no treaty, and no
controlling executive or legislative act or judicial decision, resort must be had to the customs and usages of civilized
nations; and, as evidence of these, to the works of jurists and commentators, who by years of labor, research and
experience, have made themselves peculiarly well acquainted with the subjects of which they treat. Such works are
resorted to by judicial tribunals, not for the speculations of their authors concerning what the law ought to be, but for
trustworthy evidence of what the law really is.”).
160 Refer to § 3.1.1 (DoD Practice of Applying Law of War Rules Even When Not Technically Applicable).
161 Consider VCLT art. 26 (“Every treaty in force is binding upon the parties to it and must be performed by them in
good faith.”).
162 Consider VCLT art. 24 (“1. A treaty enters into force in such manner and upon such date as it may provide or as
the negotiating States may agree. 2. Failing any such provision or agreement, a treaty enters into force as soon as
consent to be bound by the treaty has been established for all the negotiating States. 3. When the consent of a State
to be bound by a treaty is established on a date after the treaty has come into force, the treaty enters into force for
that State on that date, unless the treaty otherwise provides.
4. The provisions of a treaty regulating the
authentication of its text, the establishment of the consent of States to be bound by the treaty, the manner or date of
its entry into force, reservations, the functions of the depositary and other matters arising necessarily before the entry
into force of the treaty apply from the time of the adoption of its text.”). See also DEPARTMENT OF THE ARMY
PAMPHLET 27-161-1, I International Law: Law of Peace, ¶8-12 (Sept. 1, 1979) (“An international agreement is
basically a contract between states, and elements of obligation akin to those found in municipal contract law are
present. However, as discussed in Part I, a treaty is not a contract in the common law sense of an agreement
requiring consideration. It is the assent to be bound and not reciprocity or quid pro quo that obligates the parties.”).
36
States may withdraw from a treaty.163 In some cases, a reservation may also modify the
obligations imposed by a treaty on that State.164
A treaty does not create either obligations or rights for a third State without its consent.165
Thus, a treaty generally would not be binding on non-Parties to the treaty or create rights or
obligations for a non-Party to the treaty with respect to a Party to the treaty. Instead, a treaty
only creates law (i.e., rights that may be invoked) as between the States that are Parties to it.166
1.10.1.2 Legal Force of Customary International Law Among States. The
customary law of war generally binds all States. However, States that have objected to a
customary international law rule during its development are not bound by that rule.167
1.10.1.3 Predominately Inter-State Nature of International Obligations.
International obligations are generally viewed as running to other States, although individuals
may have responsibility under international law.
Traditionally, international law has governed relations between States, although over time
it has increasingly regulated the relationships between States and persons. Under the traditional
view, a State’s international law obligations run to other States, even when the obligations relate
to an individual (e.g., by protecting that individual), such that individuals’ “place in international
life depends largely on their status as nationals of states.”168 For example, the 1949 Geneva
Conventions and the customary law of war do not provide a private right for individuals to claim
compensation directly from a State for violations of the law of war; rather, such claims are made
by other States.169
International law has long prescribed certain rules regulating the conduct of
individuals.170 Under international law, there may be responsibility for individuals, apart from
163 Refer to § 1.7.3 (Withdrawal From Treaties).
164 Refer to § 1.7.2 (Reservations to Treaties).
165 Consider VCLT art. 34 (“A treaty does not create either obligations or rights for a third State without its
consent.”).
166 Case Concerning Certain German Interests in Polish Upper Silesia (Merits) (Germany v. Poland) 1925 P.C.I.J.
(series A) No. 7, at 29 (“A treaty only creates law as between the States which are parties to it; in case of doubt, no
rights can be deduced from it in favour of third States.”).
167 Refer to § 1.8.4 (Objection During Development).
168 I RESTATEMENT (THIRD) OF FOREIGN RELATIONS LAW OF THE UNITED STATES 71 (1987). See also II
RESTATEMENT (THIRD) OF FOREIGN RELATIONS LAW OF THE UNITED STATES 217 (§713, comment a) (1987)
(explaining that in principle, state responsibility for injury to the nationals of other states “is to the state of the
alien’s nationality and gives that state a claim against the offending state. The claim derives from injury to an
individual, but once espoused it is the state’s claim, and can be waived by the state.”).
169 Refer to § 18.16.4 (No Private Right to Compensation Under Customary International Law or the 1949 Geneva
Conventions).
170 See Sosa v. Alvarez-Machain, 542 U.S. 692, 715 (2004) (noting that international law has included “a body of
judge-made law regulating the conduct of individuals situated outside domestic boundaries” and “rules binding
individuals for the benefit of other individuals [that] overlapped with the norms of state relationships”).
37
State responsibility.171
1.10.1.4 Force of International Law Notwithstanding a State’s Domestic Law. A
State’s domestic law does not justify that State’s noncompliance with an international obligation
as a matter of international law.172 Similarly, the fact that a State’s domestic law does not
provide for a penalty with respect to a violation of international law does not relieve a person
from responsibility for that act under international law.173
1.10.2 Force of the Law of War Under U.S. Domestic Law. The specific legal force of a
law of war rule under U.S. domestic law may depend on whether that rule takes the form of a
self-executing treaty, non-self-executing treaty, or customary international law.
Longstanding DoD policy has been to require DoD personnel to comply with the law of
war obligations of the United States.174
Even if a violation of a rule is not directly punishable under U.S. law, a variety of tools in
U.S. domestic law may be used to enforce a law of war obligation of the United States. For
example, a violation of a law of war obligation may be made punishable through implementation
of the obligation in military instructions, regulations, and procedures.175
1.10.2.1 Force of Self-Executing and Non-Self-Executing Treaties Under U.S.
Domestic Law. Under domestic law, treaties to which the United States is a Party are part of
U.S. law.176
The terms “self-executing” and “non-self-executing” may be used to explain how a treaty
is to take effect in U.S. domestic law. A treaty may be classified as a self-executing treaty that
“operates of itself, without the aid of any legislative provision,” or as a non-self-executing treaty
that would require “that the Legislature must execute the contract before it can become a rule for
the Court.”177
171 Refer to § 18.22.1 (Individual Criminal Responsibility for Acts Constituting Crimes Under International Law).
172 Secretary of State Bayard, Instruction to Mr. Connery, charge to Mexico, Nov. 1, 1887, II MOORE’S DIGEST 235
(“[A] government can not appeal to its municipal regulations as an answer to demands for the fulfillment of
international duties. Such regulations may either exceed or fall short of the requirements of international law, and in
either case that law furnishes the test of the nation’s liability and not its own municipal rules.”). Consider VCLT art.
27 (“A party may not invoke the provisions of its internal law as justification for its failure to perform a treaty. This
rule is without prejudice to article 46.”).
173 Refer to § 18.22.2 (Absence of Penalty Under Domestic Law Does Not Relieve a Person of Responsibility).
174 Refer to § 18.1.1 (DoD Policy on Implementing and Enforcing the Law of War).
175 Refer to § 18.7 (Instructions, Regulations, and Procedures to Implement and Enforce the Law of War).
176 See U.S. CONSTITUTION art. VI (“This Constitution, and the laws of the United States which shall be made in
pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be
the supreme law of the land; and the judges in every state shall be bound thereby, anything in the Constitution or
laws of any State to the contrary notwithstanding.”).
177 Foster & Elam v. Neilson 27 U.S. 253, 314 (1829) (Marshall, C.J.). See also Whitney v. Robertson, 124 U.S.
190, 194 (1888) (“A treaty is primarily a contract between two or more independent nations, and is so regarded by
writers on public law. For the infraction of its provisions a remedy must be sought by the injured party through
38
1.10.2.2 Force of Customary International Law Under U.S. Domestic Law. The
customary law of war is part of U.S. law insofar as it is not inconsistent with any treaty to which
the United States is a Party, or a controlling executive or legislative act.178
1.11 JUS AD BELLUM
The law of war has been categorized into jus ad bellum (law concerning the resort to
force) and jus in bello (law concerning conduct during war).179 Although jus ad bellum is an
essential part of the law of war to consider in the political process of whether to resort to military
force, this manual focuses on jus in bello.180 Although jus in bello rules generally operate
independently of whether a side has comported with jus ad bellum in the resort to force, parts of
jus ad bellum are relevant to jus in bello.181
This section provides a brief overview of some basic aspects of jus ad bellum. Jus ad
bellum issues might raise questions of national policy that, in the Executive Branch, would be
decided by the President. In U.S. practice, legal advice provided to national-level principal
officials on such issues generally would need to be addressed through interagency discussions
coordinated by the legal adviser to the National Security Council, including consultation and
coordination among senior counsel of relevant U.S. departments and agencies.
1.11.1 Jus ad Bellum Criteria. Certain jus ad bellum criteria have, at their philosophical
roots, drawn from principles that have been developed as part of the Just War Tradition.182
These principles have included:
reclamations upon the other. When the stipulations are not self-executing, they can only be enforced pursuant to
legislation to carry them into effect, and such legislation is as much subject to modification and repeal by Congress
as legislation upon any other subject. If the treaty contains stipulations which are self-executing, that is, require no
legislation to make them operative, to that extent they have the force and effect of a legislative enactment.”);
Medellin v. Texas, 552 U.S. 491, 525-26 (2008) (“The responsibility for transforming an international obligation
arising from a non-self-executing treaty into domestic law falls to Congress.”).
178 The Paquete Habana, 175 U.S. 677, 700 (1900) (“International law is part of our law, … where there is no treaty
and no controlling executive or legislative act or judicial decision, resort must be had to the customs and usages of
civilized nations,”).
179 See, e.g., WILLIAM O‘BRIEN, THE CONDUCT OF JUST AND LIMITED WAR 9 (1981) (defining jus ad bellum as the
“doctrines concerning permissible recourse to war” and jus in bello as “the just conduct of war”); MICHAEL
WALZER, JUST AND UNJUST WARS 21 (1977) (“War is always judged twice, first with reference to the reasons states
have for fighting, secondly with reference to the means they adopt. The first kind of judgment is adjectival in
character: we say that a particular war is just or unjust. The second is adverbial: we say that a war is being fought
justly or unjustly. Medieval writers made the difference a matter of prepositions, distinguishing jus ad bellum, the
justice of war, from jus in bello, justice in war.”). But see Robert Kolb, Origin of the twin terms jus ad bellum/jus in
bello, 37 INTERNATIONAL REVIEW OF THE RED CROSS 553 (Sept.-Oct. 1997) (“The august solemnity of Latin confers
on the terms jus ad bellum and jus in bello the misleading appearance of being centuries old. In fact, these
expressions were only coined at the time of the League of Nations and were rarely used in doctrine or practice until
after the Second World War, in the late 1940s to be precise.”).
180 Refer to § 1.1.2 (Scope).
181 Refer to § 3.5 (Relationship Between Jus in Bello and Jus ad Bellum).
182 Refer to § 1.6.4 (Just War Tradition).
39
• a competent authority to order the war for a public purpose;
• a just cause (such as self-defense);
• the means must be proportionate to the just cause;
• all peaceful alternatives must have been exhausted; and
• a right intention on the part of the just belligerent.183
These principles may be reflected in modern law of war rules. For example, the Charter
of the United Nations recognizes the inherent right of States to use force in individual or
collective self-defense—a just cause for military action.184
These principles have also been incorporated into military doctrine.185
1.11.1.1 Competent Authority (Right Authority) to Wage War for a Public
Purpose. One longstanding criterion for a just war is that war must be ordered by a competent
authority for a public purpose. This jus ad bellum principle (sometimes called right authority)
acknowledges that the resort to military force is a prerogative of the State.186
The criterion that war must be ordered by a competent authority for a public purpose is
reflected in the requirement that armed groups must belong to a State to receive the privileges of
combatant status.187 This criterion is also reflected in the general denial to private persons of the
entitlement to the privileges of combatant status.188 This criterion is also reflected in the
183 WILLIAM O’BRIEN, THE CONDUCT OF JUST AND LIMITED WAR 16 (1981) (“The decision to invoke the
exceptional rights of war must be based on the following criteria: there must be competent authority to order the
war for a public purpose; there must be a just cause (it may be self-defense or the protection of rights by offensive
war) and the means must be proportionate to the just cause and all peaceful alternatives must have been exhausted;
and there must be right intention on the part of the just belligerent.”).
184 Refer to § 1.11.4.1 (Use of Force in Self-Defense).
185 MARINE CORPS DOCTRINAL PUBLICATION 1-1, Strategy, 93, 95 (1997) (“[T]he just war criteria provide objective
measures from which to judge our motives. The effective strategist must be prepared to demonstrate to all sides
why the defended cause meets the criteria of just war theory and why the enemy’s cause does not. If a legitimate
and effective argument on this basis cannot be assembled, then it is likely that both the cause and the strategy are
fatally flawed.”).
186 See Talbot v. Janson, 3 U.S. 133, 160-61 (1795) (Iredell, J., concurring) (“[N]o hostilities of any kind, except in
necessary self-defence, can lawfully be practised by one individual of a nation, against an individual of any other
nation at enmity with it, but in virtue of some public authority. War can alone be entered into by national authority;
it is instituted for national purposes, and directed to national objects; and each individual on both sides is engaged in
it as a member of the society to which he belongs, not from motives of personal malignity and ill will.”); VATTEL,
THE LAW OF NATIONS 235 (3.1.4) (“It is the sovereign power alone, therefore, which has the right to make war.”);
GROTIUS, LAW OF WAR & PEACE 97 (1.3.4.2) (“But because the whole state is endangered by war, provision has
been made by the laws of almost every state that war may be waged only under the authority of him who holds the
sovereign power in the state.”).
187 Refer to § 4.6.2 (Belonging to a Party to the Conflict).
188 Refer to § 4.18.3 (Private Persons Who Engage in Hostilities - Lack of the Privileges of Combatant Status).
40
condemnation under international law of certain types of private acts of hostility (such as piracy
or terrorism) outside the context of patriotic resistance against an enemy State during
international armed conflict.189
1.11.1.2 The Means Must Be Proportionate to the Just Cause (Proportionality -
Jus ad Bellum). Proportionality involves a weighing of the contemplated actions with the
justification for taking action.190 For example, the proportionality of the measures taken in self-
defense is to be judged according to the nature of the threat being addressed.191 Force may be
used in self-defense, but only to the extent that it is required to repel the armed attack and to
restore the security of the party attacked.192 As an illustration, assessing the proportionality of
measures taken in self-defense may involve considerations of whether an actual or imminent
attack is part of an ongoing pattern of attacks or what force is reasonably necessary to discourage
future armed attacks or threats thereof.193
The jus ad bellum criterion of proportionality is different from the jus in bello rule of
proportionality in conducting attacks.194 These concepts should not be confused with one
another.195
189 Refer to § 4.18.5 (Private Persons Who Engage in Hostilities and the Law of War).
190 Refer to § 2.4 (Proportionality).
191 William H. Taft IV, Legal Adviser, Department of State, Self-Defense and the Oil Platforms Decision, 29 YALE
JOURNAL OF INTERNATIONAL LAW 295, 305-06 (2004) (“There is no requirement in international law that a State
exercising its right of self-defense must use the same degree or type of force used by the attacking State in its most
recent attack. Rather, the proportionality of the measures taken in self-defense is to be judged according to the
nature of the threat being addressed… . A proper assessment of the proportionality of a defensive use of force
would require looking not only at the immediately preceding armed attack, but also at whether it was part of an
ongoing series of attacks, what steps were already taken to deter future attacks, and what force could reasonably be
judged to be needed to successfully deter future attacks.”).
192 Counter-memorial and Counter-claim Submitted by the United States of America, International Court of Justice,
Case Concerning Oil Platforms (Iran v. United States) 141 (¶4.31) (Jun. 23, 1997) (“Actions in self-defense must be
proportionate. Force can be used in self-defense, but only to the extent that it is required to repel the armed attack
and to restore the security of the party attacked.”).
193 Herbert S. Okun, Letter Dated 14 April 1986 from the Acting Permanent Representative of the United States of
America to the United Nations Addressed to the President of the Security Council, U.N. Doc. S/17990 (Apr. 14,
1986) (“The United States objective was to destroy facilities used to carry out Libya’s hostile policy of international
terrorism and to discourage Libyan terrorist attacks in the future. These facilities constituted essential elements
which have enabled Libyan agents to carry out deadly missions against U.S. installations and innocent
individuals.”); Madeleine Albright, Letter Dated 26 June 1993 from the Permanent Representative of the United
States of America to the United Nations Addressed to the President of the Security Council, U.N. Doc. S/26003 (Jun.
26, 1993) (“Accordingly, as a last resort, the United States has decided that it is necessary to respond to the
attempted attack and the threat of further attacks by striking at an Iraqi military and intelligence target that is
involved in such attacks. … It is the sincere hope of the United States Government that such limited and
proportionate action may frustrate future unlawful actions on the part of the Government of Iraq and discourage or
preempt such activities.”).
194 Refer to § 5.12 (Proportionality in Conducting Attacks).
195 Refer to § 3.5.1 (General Distinction Between Jus in Bello and Jus ad Bellum).
41
1.11.1.3 All Peaceful Alternatives Must Have Been Exhausted (Necessity - Jus ad
Bellum). The jus ad bellum condition of necessity requires that no reasonable alternative means
of redress are available.196 For example, in exercising the right of self-defense, diplomatic
means must be exhausted or provide no reasonable prospect of stopping the armed attack or
threat thereof.197
The jus ad bellum criterion of necessity is different from the jus in bello concept of
military necessity.198
1.11.2 U.N. Charter Framework and the U.N. Security Council. The Charter of the
United Nations provides the modern treaty framework for jus ad bellum. Under the Charter of
the United Nations, the U.N. Security Council has primary responsibility for the maintenance of
international peace and security.199 The U.N. Security Council may determine the existence of
any threat to the peace, breach of the peace, or act of aggression, and may decide what measures
shall be taken under the Charter to maintain or restore international peace and security.200 For
example, the U.N. Security Council may recognize that a State is acting lawfully in self-defense
or that another State is the aggressor in an armed conflict.201 In addition, the U.N. Security
Council may authorize the use of military force.202
196 William H. Taft IV, Legal Adviser, Department of State, Self-Defense and the Oil Platforms Decision, 29 YALE
JOURNAL OF INTERNATIONAL LAW 295, 304 (2004) (“The condition of ‘necessity,’ rather, requires that no
reasonable alternative means of redress are available.”).
197 For example, Madeleine Albright, Letter Dated 26 June 1993 from the Permanent Representative of the United
States of America to the United Nations Addressed to the President of the Security Council, U.N. Doc. S/26003 (Jun.
26, 1993) (“Based on the pattern of the Government of Iraq’s behavior, including the disregard for international law
and Security Council resolutions, the United States has concluded that there is no reasonable prospect that new
diplomatic initiatives or economic measures can influence the current Government of Iraq to cease planning future
attacks against the United States. Accordingly, as a last resort, the United States has decided that it is necessary to
respond to the attempted attack and the threat of further attacks by striking at an Iraqi military and intelligence target
that is involved in such attacks.”); Thomas R. Pickering, Letter Dated 20 December 1989 from the Permanent
Representative of the United States of America to the United Nations Addressed to the President of the Security
Council, U.N. Doc. S/21035 (Dec. 20, 1989) (“The United States has exhausted every available diplomatic means to
resolve peacefully disputes with Mr. Noriega, who has rejected all such efforts. Action by the United States was
taken after Mr. Noriega declared on 15 December that a state of war existed with the United States, and following
brutal attacks by forces of Mr. Noriega on lawfully present American personnel, murdering one American and
injuring and threatening others.”).
198 Refer to § 2.2 (Military Necessity).
199 U.N. CHARTER art. 24(1) (“In order to ensure prompt and effective action by the United Nations, its Members
confer on the Security Council primary responsibility for the maintenance of international peace and security, and
agree that in carrying out its duties under this responsibility the Security Council acts on their behalf.”).
200 U.N. CHARTER art. 39 (“The Security Council shall determine the existence of any threat to the peace, breach of
the peace, or act of aggression and shall make recommendations, or decide what measures shall be taken in
accordance with Articles 41 and 42, to maintain or restore international peace and security.”).
201 For example, U.N. SECURITY COUNCIL RESOLUTION 661, U.N. Doc. S/RES/661 (1990) (“Affirming the inherent
right of individual or collective self-defence, in response to the armed attack of Iraq against Kuwait, in accordance
with Article 51 of the Charter,”); U.N. SECURITY COUNCIL RESOLUTION 1368, U.N. Doc. S/RES/1368 (2001)
(“Determined to combat by all means threats to international peace and security caused by terrorist acts, Recognizing
the inherent right of individual or collective self-defence in accordance with the Charter, 1. Unequivocally condemns
in the strongest terms the horrifying terrorist attacks which took place on 11 September 2001 in New York,
42
1.11.2.1 U.N. Member State Obligations With Respect to U.N. Security Council
Decisions. Members of the United Nations have agreed to give the United Nations every
assistance in any action it takes in accordance with the Charter and to refrain from giving
assistance to any State against which the United Nations is taking preventive or enforcement
action.203
Members of the United Nations have agreed to accept and carry out the decisions of the
U.N. Security Council in accordance with the Charter.204 They have also agreed to join in
affording mutual assistance in carrying out the measures decided upon by the U.N. Security
Council.205
Moreover, in the event of a conflict between the obligations of the Members of the
United Nations under the Charter and their obligations under any other international agreement,
their obligations under the Charter prevail.206
1.11.3 Prohibition on Certain Uses of Force. Under Article 2(4) of the Charter of the
United Nations, “[a]ll Members shall refrain in their international relations from the threat or use
of force against the territorial integrity or political independence of any State, or in any other
manner inconsistent with the Purposes of the United Nations.207 Numerous other treaties also
reflect these prohibitions on the threat or use of force.208
Washington, D.C. and Pennsylvania and regards such acts, like any act of international terrorism, as a threat to
international peace and security;”).
202 Refer to § 1.11.4.2 (Use of Force Authorized by the U.N. Security Council Acting Under Chapter VII of the
Charter of the United Nations).
203 U.N. CHARTER art. 2(5) (“All Members shall give the United Nations every assistance in any action it takes in
accordance with the present Charter, and shall refrain from giving assistance to any state against which the United
Nations is taking preventive or enforcement action.”).
204 U.N. CHARTER art. 25 (“The Members of the United Nations agree to accept and carry out the decisions of the
Security Council in accordance with the present Charter.”).
205 U.N. CHARTER art. 49 (“The Members of the United Nations shall join in affording mutual assistance in carrying
out the measures decided upon by the Security Council.”).
206 U.N. CHARTER art. 103 (“In the event of a conflict between the obligations of the Members of the United Nations
under the present Charter and their obligations under any other international agreement, their obligations under the
present Charter shall prevail.”).
207 U.N. CHARTER art. 2(4).
208 See, e.g., Inter-American Treaty of Reciprocal Assistance, art. 1, Sept. 2, 1947, 62 STAT. 1681, 1700 (“The High
Contracting Parties formally condemn war and undertake in their international relations not to resort to the threat or
the use of force in any manner inconsistent with the provisions of the Charter of the United Nations or of this
Treaty.”); Treaty Providing for the Renunciation of War as an Instrument of National Policy, art. 1, Aug. 27, 1928,
46 STAT. 2343, 2345-46 (“The High Contracting Parties solemnly declare in the names of their respective peoples
that they condemn recourse to war for the solution of international controversies, and renounce it as an instrument of
national policy in their relations with one another.”).
43
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