Law of War and Armed Conflict

1. Meaning and Scope

The law of war and armed conflict is the body of international legal rules governing the existence, conduct, and consequences of armed conflict. It addresses the protection of persons affected by hostilities, the permissible means and methods of warfare, the treatment of prisoners, the status of combatants, and the responsibilities of parties to a conflict.

The expression is closely associated with international humanitarian law (IHL), traditionally known as the law of war or the law of armed conflict. However, the legality of resorting to force is governed by a separate framework of international law.

Three major legal frameworks must therefore be distinguished:

1. Jus ad bellum: the law governing whether force may lawfully be used.
2. International humanitarian law: the rules governing conduct during armed conflict.
3. International human rights law: the rules protecting individuals, which continue to apply during armed conflict subject to the applicable legal framework.

These bodies of law serve related but distinct purposes. A state may resort to force unlawfully while its forces remain bound by humanitarian law. Likewise, a party acting in lawful self-defence is not exempt from restrictions on its conduct during hostilities.

2. Historical Development

2.1 Ancient and Medieval Warfare

Ancient societies developed customs and rules concerning truces, the treatment of captives, diplomatic protection, and the conduct of warfare. Religious traditions and philosophical systems also influenced ideas about legitimate warfare and the treatment of opponents.

These historical practices were diverse and did not constitute a uniform international legal system.

2.2 The Development of Modern Humanitarian Law

The nineteenth century marked a significant transition toward codified rules intended to reduce suffering during warfare.

The work of Henry Dunant, following his observations of the Battle of Solferino in 1859, helped inspire the humanitarian movement that led to the establishment of the International Committee of the Red Cross (ICRC) in 1863 and the adoption of the First Geneva Convention in 1864.

2.3 The Hague Conventions

The Hague Peace Conferences of 1899 and 1907 contributed to the development of rules governing the conduct of hostilities, the means and methods of warfare, and the peaceful settlement of disputes.

The Hague tradition is commonly associated with restrictions on how wars may be fought, while the Geneva tradition is particularly associated with the protection of persons affected by armed conflict. The two traditions overlap and form part of modern international humanitarian law.

2.4 The Geneva Conventions of 1949

The four Geneva Conventions of 12 August 1949 are central instruments of modern humanitarian law. They protect wounded and sick members of armed forces on land, wounded, sick and shipwrecked members of armed forces at sea, prisoners of war, and civilians in time of war.

Common Article 3 establishes minimum protections for certain persons in non-international armed conflicts.

2.5 The Additional Protocols of 1977

Additional Protocols I and II, adopted in 1977, developed rules concerning the protection of victims of international armed conflicts and certain non-international armed conflicts.

Additional Protocol I addresses international armed conflicts within its scope, while Additional Protocol II supplements the rules applicable to certain non-international armed conflicts. Their precise treaty applicability depends on the parties and circumstances, and relevant customary rules may apply independently.

3. Classification of Armed Conflicts

The legal classification of a conflict determines which rules apply. Classification is based primarily on objective facts, rather than on the labels chosen by the parties.

3.1 International Armed Conflict

An international armed conflict generally arises when there is resort to armed force between states. A formal declaration of war is not required.

The occupation of the territory of another state can trigger the application of the law governing international armed conflict even when the occupation encounters no armed resistance.

3.2 Non-International Armed Conflict

A non-international armed conflict generally involves sufficiently intense armed violence between state authorities and organized armed groups, or between such groups within a state.

Two important factors are commonly assessed:

• The organization of the armed groups.
• The intensity and duration of the violence.

Isolated riots, internal disturbances, and sporadic acts of violence do not automatically amount to a non-international armed conflict.

3.3 Internationalized Conflicts

A conflict may involve both domestic and international dimensions. Foreign intervention, support for armed groups, and direct hostilities between states can raise complex classification questions.

The legal classification of different relationships or phases within a conflict may vary. Foreign involvement does not automatically transform every confrontation within a country into an international armed conflict.

3.4 Occupation

Occupation arises when territory is actually placed under the authority of a hostile army, under the applicable legal test. The law of occupation imposes obligations on the occupying power and does not transfer sovereignty over the occupied territory merely because effective control has been established.

4. Fundamental Principles of the Law of Armed Conflict

4.1 Distinction

Parties to an armed conflict must distinguish between civilians and combatants and between civilian objects and military objectives. Attacks may be directed only at lawful military objectives.

Civilians are protected against direct attack unless and for such time as they directly participate in hostilities, subject to the applicable legal rules.

4.2 Proportionality in Attack

An attack is prohibited if the expected incidental civilian death, injury, or damage to civilian objects would be excessive in relation to the concrete and direct military advantage anticipated.

This rule requires an assessment based on the information reasonably available at the relevant time. It does not establish a simple numerical ratio between civilian casualties and military advantage.

4.3 Precautions in Attack

Parties must take feasible precautions to verify targets, choose means and methods that reduce civilian harm, assess expected incidental harm, and cancel or suspend attacks when required by the applicable rules.

The attacking party must give effective advance warning of attacks that may affect the civilian population, when circumstances permit.

4.4 Military Necessity

Military necessity permits only those measures that are lawful under international humanitarian law and that are necessary to achieve a legitimate military purpose. It is not a general justification for ignoring humanitarian protections.

4.5 Humanity

The principle of humanity seeks to prevent unnecessary suffering and protect persons who are not, or are no longer, participating in hostilities.

4.6 Prohibition of Unnecessary Suffering

Weapons and methods of warfare are subject to restrictions intended to prevent superfluous injury or unnecessary suffering, as well as other specific prohibitions under treaty and customary law.

4.7 Equal Application

International humanitarian law applies to all parties to an armed conflict, regardless of which party initiated the conflict or which side is considered politically or morally justified.

5. Combatants and Civilians

5.1 Combatant Status

In international armed conflicts, members of the armed forces of a party generally have combatant status, subject to the applicable legal rules and exceptions.

Combatant status is important because lawful combatants may participate directly in hostilities and, if captured and entitled to prisoner-of-war status, receive the corresponding protections.

5.2 Civilians

Civilians are persons who are not members of the armed forces or otherwise included in a category treated as combatants under the applicable law.

Civilians must not be made the object of direct attack unless and for such time as the relevant exception concerning direct participation in hostilities applies.

5.3 Civilian Objects

Civilian objects are protected against attack unless they qualify as military objectives under the applicable legal test. An object qualifies as a military objective only when, by its nature, location, purpose, or use, it makes an effective contribution to military action and its destruction, capture, or neutralization offers a definite military advantage in the circumstances ruling at the time.

5.4 Dual-Use Objects

Infrastructure such as bridges, communications networks, energy facilities, and transport systems may serve both civilian and military functions. Whether an individual object qualifies as a military objective must be assessed under the applicable legal criteria.

Its military use does not remove the obligation to apply proportionality and take feasible precautions.

6. Prisoners of War and Persons in Enemy Hands

6.1 Prisoner-of-War Status

The Third Geneva Convention regulates the treatment of prisoners of war in international armed conflicts. Entitlement to this status depends on the applicable legal categories and circumstances.

Not every detained person in an armed conflict automatically qualifies as a prisoner of war.

6.2 Humane Treatment

Prisoners of war must be treated humanely. Violence, intimidation, insults, and public curiosity are restricted under the applicable rules. Torture and cruel treatment are prohibited.

6.3 Interrogation and Judicial Guarantees

Prisoners of war are subject to specific protections concerning interrogation, discipline, prosecution, and judicial proceedings. They cannot be compelled to provide more than the information permitted by the applicable rules.

6.4 Release and Repatriation

The Third Geneva Convention contains rules governing release and repatriation, including repatriation without delay after the cessation of active hostilities, subject to the Convention’s terms and applicable exceptions.

7. Protection of Civilians

7.1 Civilian Protection

Civilians must be protected against the dangers arising from military operations. Parties must not deliberately direct attacks against civilians or civilian objects.

7.2 Forced Displacement

Forced displacement of civilians is prohibited except where the security of the civilians involved or imperative military reasons require evacuation under the applicable legal framework. Displacement may also raise issues under human rights law and other rules.

7.3 Humanitarian Relief

Impartial humanitarian relief operations are subject to rules intended to facilitate assistance to civilians in need. The parties must respect and protect authorized humanitarian personnel and relief operations under the applicable legal framework.

7.4 Medical Personnel and Facilities

Medical personnel, medical units, and medical transports receive special protection under international humanitarian law. They must not be attacked while entitled to protection, and their humanitarian duties must be respected.

7.5 Children in Armed Conflict

Children receive general civilian protection and additional protections under applicable humanitarian and human rights law. International rules also restrict the recruitment and use of children in hostilities, with the details depending on the relevant legal instrument and context.

8. Means and Methods of Warfare

8.1 Weapons Restrictions

International law restricts or prohibits particular weapons because of their effects, indiscriminate nature, unnecessary suffering, or other legal concerns.

Specific treaties regulate weapons such as chemical weapons, biological weapons, and certain conventional weapons. Nuclear weapons raise particularly complex questions under international law, including the principles of distinction and proportionality and the rules governing the use of force.

8.2 Indiscriminate Attacks

Indiscriminate attacks are prohibited. These include attacks that are not directed at a specific military objective, employ means or methods that cannot be directed at such an objective as required by law, or have effects that cannot be limited as required by the applicable rules.

8.3 Perfidy

Perfidy involves inviting the confidence of an adversary to lead it to believe that it is entitled to, or is obliged to accord, protection under international law, with the intent to betray that confidence. Certain acts of perfidy are prohibited.

8.4 Feints and Ruses of War

Ruses of war, including camouflage, decoys, and misleading military information, may be lawful when they do not violate applicable legal rules. They must be distinguished from prohibited perfidy.

8.5 Siege and Starvation

The law of armed conflict imposes restrictions on siege warfare and prohibits starving civilians as a method of warfare. Humanitarian relief and civilian protection obligations remain relevant even during prolonged hostilities.

9. War Crimes and Accountability

War crimes are serious violations of international humanitarian law that give rise to individual criminal responsibility under applicable law.

Examples may include intentionally directing attacks against civilians, torture, wilful killing of protected persons, taking hostages, and certain forms of unlawful destruction or appropriation of property.

9.1 Individual Criminal Responsibility

Individuals may be held criminally responsible for war crimes under national law or the applicable international criminal jurisdiction. Responsibility can arise through direct commission and, under defined conditions, ordering, aiding, abetting, or other forms of participation.

9.2 Command Responsibility

Commanders and other superiors may incur criminal responsibility under applicable legal standards where they knew, or under the relevant rule had reason to know, of crimes by subordinates and failed to take necessary and reasonable measures to prevent or repress them or submit the matter to competent authorities.

The precise standard depends on the applicable legal framework.

9.3 International Criminal Court

The International Criminal Court may prosecute individuals for crimes within its jurisdiction, including war crimes, subject to the Rome Statute’s jurisdictional and admissibility requirements.

The Court does not prosecute states as criminal defendants. State responsibility and individual criminal responsibility are separate legal frameworks.

10. Relationship with International Human Rights Law

International humanitarian law and international human rights law may apply simultaneously during armed conflict. Humanitarian law is specially adapted to the circumstances of armed conflict, while human rights law protects individuals against violations by states and, under certain frameworks, addresses obligations in other circumstances.

Questions of extraterritorial jurisdiction, derogation, and the relationship between specific rules require careful examination. The existence of armed conflict does not automatically suspend all human rights obligations.

11. Contemporary Challenges

Modern armed conflicts increasingly involve urban warfare, cyber operations, autonomous technologies, private military and security companies, and armed groups operating across borders.

These developments raise questions about target verification, civilian protection, attribution, accountability, and the practical implementation of humanitarian rules.

The underlying legal principles remain relevant even when the weapons, actors, and operational environments change. The challenge is to ensure that existing rules are implemented effectively and that any new instruments address genuine legal gaps.

12. Conclusion

The law of war and armed conflict seeks to limit the suffering caused by armed violence while recognizing that military operations may occur under specific legal conditions. Its core principles include distinction, proportionality, precautions, humane treatment, and restrictions on unlawful means and methods of warfare.

Its application does not depend on which side is considered the aggressor. All parties must comply with the applicable rules, and serious violations may result in state responsibility, individual criminal responsibility, or both.

36 Key Takeaways for Exams

1. The law of armed conflict regulates conduct and protections during armed conflict.
2. Jus ad bellum governs the legality of resorting to force.
3. International humanitarian law is also known as the law of war or law of armed conflict.
4. International human rights law may continue to apply during armed conflict.
5. Henry Dunant helped inspire the modern humanitarian movement.
6. The International Committee of the Red Cross was established in 1863.
7. The First Geneva Convention was adopted in 1864.
8. The Hague Conventions contributed to rules governing warfare.
9. The four Geneva Conventions were adopted in 1949.
10. Common Article 3 establishes minimum protections in certain non-international armed conflicts.
11. Additional Protocols I and II were adopted in 1977.
12. Classification of armed conflict depends primarily on objective facts.
13. International armed conflict generally involves armed force between states.
14. Non-international armed conflict requires sufficient organization and intensity of violence.
15. Occupation does not transfer sovereignty over territory.
16. Distinction requires separating civilians and civilian objects from lawful military targets.
17. Proportionality prohibits expected incidental civilian harm excessive in relation to anticipated concrete and direct military advantage.
18. Feasible precautions must be taken to reduce civilian harm.
19. Military necessity does not override humanitarian law.
20. International humanitarian law applies to all parties to an armed conflict.
21. Combatant and prisoner-of-war status depend on applicable legal rules.
22. Prisoners of war must be treated humanely.
23. Civilians are protected against direct attack, subject to the applicable rules on direct participation in hostilities.
24. Civilian objects are protected unless they qualify as military objectives.
25. Medical personnel and facilities receive special protection.
26. Forced displacement is prohibited except under defined legal conditions.
27. Starving civilians as a method of warfare is prohibited.
28. Indiscriminate attacks are prohibited.
29. Perfidy is distinct from lawful ruses of war.
30. Specific treaties prohibit or restrict particular categories of weapons.
31. War crimes may give rise to individual criminal responsibility.
32. Command responsibility depends on specific legal conditions.
33. The International Criminal Court prosecutes individuals, not states.
34. State responsibility and individual criminal responsibility are distinct.
35. New technologies do not automatically remove existing humanitarian obligations.
36. The law of armed conflict aims to limit suffering and protect persons affected by war.