International Principles Governing Wars: Provisions, Judgments, and Key Doctrines

Index of Headings

1. Introduction
2. Principle of Military Necessity
3. Principle of Distinction
4. Doctrine of Proportionality
5. Principle of Humanity (Unnecessary Suffering)
6. Principle of Impartiality
7. Principle of Neutrality
8. Principle of Independence
9. Principle of Sovereignty and State Consent
10. Principle of Accountability and Individual Criminal Responsibility
11. Principle of Protection of Prisoners of War and Detainees
12. Principle of Protection of Civilians
13. Principle of Non-Discrimination
14. Principle of Prohibition of Certain Weapons
15. Principle of Obligation to Restore Peace
16. Conclusion
17. FAQs

Introduction

The conduct of war is governed by a complex framework of international principles designed to limit suffering, protect non-combatants, and preserve some measure of humanity even amid armed conflict. These principles, rooted in international humanitarian law (IHL), customary law, and major treaties, have been shaped by historical events, landmark judgments, and evolving global consensus. Below, we explore at least ten of the most relevant international principles governing war, their legal provisions, and illustrative judicial decisions.

1.Principle of Military Necessity

Military necessity permits measures which are indispensable for securing the ends of war and are lawful under international law. However, it does not justify actions otherwise prohibited, such as targeting civilians or using banned weapons. The principle is codified in the Hague Regulations (1907) and underpins much of IHL, requiring that attacks must be directed at legitimate military objectives and that harm to civilians must be minimized.

Only those actions necessary to achieve a legitimate military objective are permitted; excessive destruction and suffering are forbidden.

The Nuremberg Trials were a series of trials undertaken by the Allied nations in Nuremberg, Germany, after World War II. The trials aimed to prosecute senior Nazi leaders for crimes against peace, war crimes, and crimes against humanity. The trials, held between 1945 and 1946, set the precedent of individual responsibility for wartime atrocities and formed the foundation of international criminal law.
The International Military Tribunal (IMT) at Nuremberg condemned the destruction of civilian property not justified by military necessity (Nuremberg Judgment, 1946).

2.Principle of Distinction

Distinction requires parties to a conflict to differentiate at all times between combatants and non-combatants (civilians), as well as between military objectives and civilian objects. Attacks may only be directed against combatants and military objectives.

Attacks on civilians or civilian objects are prohibited unless and for such time as they take a direct part in hostilities (Geneva Conventions, Additional Protocol I, Article 48).

The International Criminal Tribunal for the former Yugoslavia (ICTY) in the Tadić case emphasized the centrality of distinction in the conduct of hostilities.

The Prosecutor v. Duško Tadić
On 30 April 1992, the Serb Democratic Party (SDS) seized power in the town of Prijedor (Bosnia and Herzegovina). The nearby town of Kozarac (Bosnia and Herzegovina) was attacked on 24 May 1992, and an estimated 800 civilians were killed, and non-Serbs expelled from the town. Throughout the attack on Kozarac, non-Serb civilians were robbed and beaten, and killed by the Serb forces. Following the capture of Prijedor and its surroundings, the Serb military had held non-Serb civilians in three large prison camps: the Omarska, Keraterm, and Trnopolje camps (all outside Prijedor, Bosnia and Herzegovina). The detainees had been subjected to beatings, sexual abuse, torture, killings, and psychological cruelty. In addition, the detainees were detained in unsanitary conditions in overcrowded rooms (para. 53 et seq. of the judgment handed down by Trial Chamber II on 7 May 1997). Duško Tadić was President of the Local Board of the Serb Democratic Party in Kozarac (Bosnia and Herzegovina).

3.Doctrine of Proportionality

The International Court of Justice (below, the ICJ) addressed the issue of self-defence for the first time in 1986 in the case of Nicaragua. Before discussing the actual measures available before the Court announced that the 'Parties also agree in holding that whether the response to the attack is legal hinges on compliance with the standards of necessity and the proportionality of the actions taken in self-defence. Initially, the Court emphasized that US support to the 'contras' and mining of Nicaraguan ports and attacks on ports, oil facilities, and more by the US had been illegal because there had been no armed attack on the part of Nicaragua vs. El Salvador. It nevertheless went on to consider whether the US actions would have been necessary and proportionate if only they had been legal in the first instance. The Court pointed out that the US actions occurred a few months after the opposition to the government of El Salvador had been brought to an end.

The Court reiterated its conclusions that the 'acts of which Nicaragua is accused, even presuming them to have been created by and attributable to that State, could only have justified proportionate counter-measures on the part of the State which had been the victim of these acts, that is El Salvador, Honduras or Costa Rica. They were unable to justify third State countermeasures, the United States, and especially were unable to justify intervention with the use of force

Proportionality prohibits attacks that may cause incidental loss of civilian life or damage to civilian objects which would be excessive about the concrete and direct military advantage anticipated.

Incidental civilian harm must not be excessive compared to the military gain (Additional Protocol I, Article 51(5)(b)). In the Legality of the Threat or Use of Nuclear Weapons (ICJ, 1996), the International Court of Justice reaffirmed proportionality as a fundamental principle of IHL.

4.The Principle of Humanity (Unnecessary Suffering)

The principle of humanity forbids the infliction of suffering, injury, or destruction not necessary for achieving legitimate military objectives. It is reflected in prohibitions on weapons and methods of warfare that cause superfluous injury or unnecessary suffering.

Weapons and tactics calculated to cause unnecessary suffering are prohibited (Hague Convention IV, Article 23(d)). The Nuremberg Tribunal condemned the use of weapons and tactics that caused unnecessary suffering.

5.The Principle of Impartiality

Impartiality, especially relevant for humanitarian actors, requires that assistance and protection be provided without discrimination based on nationality, race, religion, or political opinion.

Aid must be delivered solely based on need, without adverse distinction (Geneva Conventions, Common Article 3; Red Cross Principles). International courts have stressed impartiality in the context of humanitarian relief, as seen in the ICJ’s advisory opinions.

6.The Principle of Neutrality

Neutrality obliges humanitarian actors and neutral states to abstain from taking sides in hostilities or engaging in controversies of a political, racial, religious, or ideological nature.

Humanitarian organizations must not favor any party to the conflict (Red Cross and Red Crescent Movement’s Fundamental Principles). The ICJ has recognized the importance of neutrality for the protection of humanitarian operations.

7.The Principle of Independence

Independence requires that humanitarian action be autonomous from the political, economic, military, or other objectives of actors involved in armed conflict.Humanitarian organizations must maintain independence from parties to the conflict (UNGA Resolution 58/114, 2004).

The UN Security Council, in Resolution 1894 (2009), reaffirmed independence as crucial for the protection of civilians in conflict.

8. The Principle of Sovereignty and State Consent

While IHL imposes obligations directly on parties to a conflict, the principles of state sovereignty and consent remain central to the international legal order. Humanitarian assistance often requires the consent of the state concerned, except where IHL obligations override such consent in situations of acute need. Humanitarian relief is subject to the consent of the state, but such consent cannot be arbitrarily withheld (Additional Protocol I, Article 70).

The ICJ in the Nicaragua case (1986) discussed the limits of state sovereignty in the context of humanitarian intervention.

9.The Principle of Accountability and Individual Criminal Responsibility

A cornerstone of modern international law is that individuals, including heads of state and military commanders, can be held criminally responsible for war crimes, crimes against humanity, and genocide. The Nuremberg Principles, affirmed by the UN General Assembly, established that individuals cannot escape liability by claiming to act on orders or as state officials.

Principle IV of the Nuremberg Principles: Acting on orders does not relieve individuals of responsibility, provided a moral choice was possible. The Nuremberg Judgment (1946) and subsequent cases (e.g., ICTY, ICTR, ICC) have consistently upheld this principle.

10.The Principle of Protection of Prisoners of War and Detainees

IHL requires humane treatment of prisoners of war (POWs) and prohibits torture, cruel, or degrading treatment. The Geneva Conventions set out detailed protections for POWs, the wounded, and civilians in enemy hands.

Geneva Convention III (1949) and Common Article 3 require humane treatment of all detainees.

The United States Supreme Court in Hamdan v. Rumsfeld (2006) affirmed the applicability of Common Article 3 to all armed conflicts.

11.The Principle of Protection of Civilians

The protection of civilians is a foundational principle of IHL. Parties to a conflict must take constant care to spare the civilian population and civilian objects from the effects of hostilities.

Attacks must not be directed against civilians; precautions must be taken to minimize harm (Additional Protocol I, Article 57).

The ICTY and ICC have prosecuted individuals for direct and indiscriminate attacks on civilians.

12.The Principle of Non-Discrimination

Non-discrimination underpins the application of IHL, ensuring that protections apply regardless of race, religion, or other status.

Geneva Conventions, Common Article 3, prohibits discrimination in the treatment of persons not taking active part in hostilities. International courts have consistently affirmed non-discrimination as a core tenet of humanitarian law.

One of the earliest judgements at the international level to decide the extent of the principle of non-discrimination was made by the European Court in the Belgian Linguistic case decision (case 'Relating to Certain Aspects of the Laws on the Use of Languages in Education in Belgium, Application Nos. 1474/62, 1677/62, 1691/62, 1769/63, 1994/63, 2126/64, Judgements of 23 July 1968). In this judgment, the European Court concurred that not all forms of differential treatment in offering rights and freedoms amount to forbidden discrimination under the Convention. In this judgment, the Court articulated its analytical framework for identifying whether forbidden discrimination has taken place (para. 10):

a. the facts reveal a differential treatment;
b. the difference is not objective, i.e., it does not have a purpose and legitimate reason in consideration of the purpose and effects of the measure concerned; and
c. there is no proportionality between the means used and the purpose pursued to be attained.

13.The Principle of Prohibition of Certain Weapons

International law prohibits or restricts the use of certain weapons deemed to cause unnecessary suffering or have indiscriminate effects, such as chemical, biological, and anti-personnel landmines.

Chemical Weapons Convention (1993), Biological Weapons Convention (1972), and the Ottawa Treaty (1997) on landmines. The ICJ’s Nuclear Weapons advisory opinion (1996) addressed the legality of certain weapons under IHL.

14.The Principle of Obligation to Restore Peace

The law of war aims not only to regulate hostilities but also to facilitate the restoration of peace and security. The UN Charter, Article 2(4), prohibits the use of force except in self-defense or with Security Council authorization.

The ICJ in the Oil Platforms case (2003) and others have interpreted the scope of lawful force under the Charter. The international principles governing wars form a robust legal and ethical framework aimed at limiting the horrors of armed conflict. They are codified in treaties, affirmed by international tribunals, and reflected in customary law. These principles- military necessity, distinction, proportionality, humanity, honor, impartiality, neutrality, independence, sovereignty, accountability, and others- are not merely aspirational; they are enforceable norms that carry legal consequences for violations. Through landmark judgments and continued evolution, these principles strive to balance military objectives with the imperatives of humanity and justice.

Conclusion

Finally, the international laws of war are vital guarantees to maintain humanity, legality, and justice in times of armed conflict. Based on treaties, customary law, and supplemented by judicial rulings, the principles-military necessity, distinction, proportionality, and accountability-define distinct limits for permissible behaviour and seek to safeguard individuals not taking part in hostilities. When conflicts become armed, continued respect for and application of these principles are essential to reducing suffering, holding perpetrators accountable, and maintaining respect for the rule of law even in the most extreme situations.

Frequently Asked Questions (FAQs)

1.What does the Principle of Impartiality entail?
Humanitarian aid must be delivered without discrimination, based solely on need.

Humanitarian organizations and neutral states must avoid siding with any party and remain free from ideological bias.

2.Why is the Principle of Independence crucial for humanitarian actors?
It ensures humanitarian action is autonomous and unaffected by political or military agendas.

3.What role does State Sovereignty and Consent play in humanitarian interventions?
Humanitarian aid usually requires state consent, but this cannot be withheld arbitrarily in situations of dire need.

4.What protections are guaranteed for Prisoners of War (POWs) and detainees?
They must be treated humanely without torture or cruel treatment.

5.What obligations do parties have under the Principle of Civilian Protection?
They must avoid targeting civilians and take precautions to minimize harm during military operations.

6.Which weapons are prohibited under international law?
Weapons causing unnecessary suffering or with indiscriminate effects like chemical, biological, and anti-personnel mines are banned.