War under International Law

Author: Ritika Sharma



With so many countries in the world and the positive steps of everyone towards globalization, the countries interact with each other on so many platforms. In this interaction and competition, it is not possible that there can be no dispute among the nations. For the settlement of these disputes, various ways are adopted by the nations and these ways can be divided into peaceful and coercive means. Peaceful means consist of negotiations, mediation, conciliation, inquiry, arbitration, judicial settlement, etc and coercive means are retortion, reprisals, embargo, pacific blockade, intervention. When the countries are not able to solve their disputes even with coercive means then they may resort to war.

Definitions of War

Various jurists have given different definitions of war.

In Oppenheim’s words, “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”.

Starke says that “war in its most generally understood sense was a contest between two or more states primarily through their armed forces, the ultimate purpose of each contestant or each contestant group being to vanquish the other or others and impose its own conditions of peace”.

Important elements of War which can be derived from the above mentioned definitions are:

  • War is a contention or violence between the armed forces.
  • There should be two or more than two States which are opposing each other. When groups within a single state are opposing each other, then it cannot be termed as a War.
  • Thirdly, there is the involvement of armed forces and in war, non combatants are not made the target.
  • The main object behind the war is to overpower each other so that the winning state can impose its rules on the other state.
Animus Belligerendi

Animus Belligerendi means the intention of the parties. Whether war is going on between two states or not, depends upon the intention of those states. When the States contest with each other then it can be said that they are at war when they have this intention. So the animus belligerendi of the states can be obtained from the following circumstances:

Firstly, when the states declare themselves that they are at war. It is an instance that shows the express intention on the part of states.

Secondly, when the war is not expressly declared then if,

  •  the states contesting with each other treat it like war or
  •  the States adopt some ways of force or other actions amounting to war or
  •  the third states believe that war is going on between the two states irrespective of the fact that the states in question treat it as war or not,

then it would be treated as a war.

Declaration of War

Grotius was of the view that declaration of war is very important before its commencement but in wars that occurred in the 18th and 19th century it was not followed strictly.

Article I of The Second Hague Convention, 1907 says, “The contracting powers recognize that hostilities between them must not commence without a previous and unequivocal warning, which shall take the form either of a declaration of war, giving reasons, or of an ultimatum with a conditional declaration of war”.

This provision was taken into account in World War I and the states commenced war only after giving warnings. Wars between France and Germany, Austria, and Hungry are examples of declared wars. But this practice was not followed in World War II.

For example, Germany invaded Poland and Finland in 1939, Denmark and Norway in 1940, and the Soviet Union in 1941without any prior warning. The other States too commences hostilities without any warning.[1]

Legal Regulations on War

Grotius introduced the concept of “just war” and imposed certain limitations on the unfettered power of the States to wage war. According to him war could be resorted provided the rights of others are not infringed, and consequently, the use of force, which does not violate the rights of others is not unjust. Even some of the writers of the nineteenth century made a distinction between “just and unjust wars” and between “right and wrong wars”[2]. Woosley has asserted that war may be waged to procure good or prevent evil by force, and just war is an attempt to obtain justice or prevent injustice by force, or in other words to bring back an injuring party to a right state of mind and conduct by the infliction of deserved evil.[3]

  • War and the League of Nations: There are certain rules made by the League of Nations in order to regulate war. Firstly, According to Article 12(1) of the Covenant of the League of Nations, if any dispute arises between the member states of the League then the report is to be submitted to arbitration or judicial settlement. Article 12(2) says that no state will resort to war until three months after the award by arbitrators or judicial decisions. In case of violation of the above provisions by any state of League that state would be deemed to have committed the act of war against the League of Nations.
  • War and the Pact of Paris: Pact of Paris, also called Renunciation of War or the Kellogg-Briand Pact, also made certain provisions with regard to war. This treaty was signed on August 27, 1928, in Paris. Article I of the Treaty reads, “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”. In the same way, Article II contains provisions for regulating war by stating that all the disputes among the states shall never be sought except by pacific means. But this Treaty does not prohibit war in all instances. War is resorted to in cases of self defence or against non-signatory or other similar circumstances.
  • War and United Nations: After the massive destruction in World War II, the United Nations was established which restricted the member states to use any kind of force against each other. Article 2 para 4 says, “all 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.” Article 2 para 3 directs every member state to solve the disputes only through peaceful means.
International Armed Conflict and War

International Armed Conflict is a different concept than war. War is a traditional concept and nowadays, states are involved in International Armed Conflict as they are restricted to resort to war because of the Kellogg- Briand Pact. In International Armed Conflict, there is only “armed hostility” and it does not affect the whole state. These hostilities may be on land, air, or in water.

The hostilities in Korea(1950-530, Indo-China( 1962), India-Pakistan(1965), and in the conflicts in and around the Suez Canal Zone (1956) are the non-war armed conflicts.[4]

Also Read, Rectification of Instruments

When use of force is lawful

It can be inferred from the provisions of the United Nations’ Charter that the use of force is lawful in some cases. Following are the circumstances:

  • Self-Defence: According to Grotius Right of Self-Defence is lawful as it is based upon the natural instinct of anyone. Self-preservation is the necessity and the use of force in such cases cannot be termed as unlawful. Even the Kellogg- Briand Pact which is against the war in every case supports the right to self-defence. Further, Article 51 of the Charter says that the State has an inherent right of self defence which can be exercised in case of armed attacks.
  • Enemy to the Signatories to the Charter: Articles 53(2) and 107 of the Charter provides the concept of enemy states. Enemy states mean any state which during World War II had been an enemy of any signatory of the Charter. Besides the German Reich and Japan, this definition also includes Bulgaria, Finland, Italy, Romania, and Hungry.[5] According to Article 107, if any state takes action against the enemies to the signatories of the Charter, then it would be considered lawful.
  • Domestic Jurisdiction: In the cases where the matter falls within the domestic jurisdiction of the States, it is lawful to use forces in the opinion of Kelsen. Also, according to Article 2 Para 7 of the Charter, the UN cannot intervene in matters of domestic jurisdiction. The actions should not disturb international peace and harmony and whether it disturbs the peace or not is a question which is to be decided by the Security Council.
  • Recovery of Lost Territory: When a state has lost its territory then after using peaceful means, the state can recover its lost territory by using force. This is because Article 5 of the General Assembly has distinctly specified that, “No territorial acquisition or special advantage resulting from aggression shall be recognized as lawful”.
  • Non-members of the United Nations: When the non-members of the United Nations disturb international peace and security, then the Security Council can take action against them.
 Effects of Outbreak of War
  • Consular Relations: Consular relations become restrained in case of Outbreak of war. According to Article 31 of the Vienna Convention on Consular Relations of 1963, the consular property is immune from requisition.
  • Diplomatic Relations: Like Consular Relations, diplomatic relations also get ruptured. The Diplomatic agents go to their States when the war is declared. Article 44 of the Vienna Convention on Diplomatic Relations of 1961 makes provisions so that the agents can safely leave the State.
  • Treaties: There are no settled provisions in the matter of Treaties when war occurs. Some jurists say that it breaks all the treaties between the contesting states but the majority of the jurists are of the opinion that war does not annul any treaty between the states opposing each other. It also depends upon the type of treaties. The bilateral treaties generally are annulled on the outbreak of war but treaties of recognition, boundary agreements, commercial and administrative treaties are not annulled completely.
  • Enemy Property: In the 18th century, the states used to confiscate all the enemy property, on the contrary in the 19th century this practise changed and the outbreak of war impacted the public and private property differently. Public property is confiscated whether it be warships or public vessels except anything engaged in religious or hospital duties. There is no rule that private property cannot be confiscated but it is considered as a breach of international law.
  • Contracts: There are two types of contracts namely, Executory contracts and executed contracts. Executory contracts are the ones which were made before the outbreak of war but were not performed. These contracts get annulled completely at times of war. Executed contracts are the ones in which one part has performed the obligation but the other is to perform. For example, a property was bought by State A from State B and State A received the property but payment is still due. Now, because of the outbreak of war this contract will get suspended for sometime but after the war, it would be treated as a debt.
  • Belligerent Subjects on Enemy Territory: The state which is engaged in war has a right to control the belligerents subjects so that they may not provide any assistance or confidential information to their state and they can be detained as Prisoners of War. However, it is a rule under International Law that non-combatants who cannot be suspected of providing any secret information to their state should be allowed to withdraw from the enemy state.
Human rights and war

The Universal Declaration of Human Rights was adopted by the United Nations General Assembly in 1948 and it specifies human rights. It is important that these human rights are not abrogated in any circumstance, not even in the special circumstances of warfare.The provisions under UDHR such as freedom of slavery (Article 4), freedom from torture and degrading treatment (Article 5), ensures the rights of war victims. The armed forces in case of war have to apply the humanitarian law while dealing with the people of their enemy state. Similarly, the states have a duty to follow the humanitarian law and in case of any violation, the compensation is to be paid to the injured state by the state who has violated the IHL. It strictly prohibits reprisals against the protected persons of an enemy state. Also, IHL makes the states responsible for all the actions performed by its armed forces.


The International Law has made all provisions to prohibit the states to engage themselves in war with anyone. Peaceful means should be adopted in case of disputes between states as the consequences of war are always harmful and grave. Various International Organisations aim to solve conflict through peaceful means like arbitration and judicial settlement in order to maintain International harmony and security.

[1] H.O. Aggarwal International Law and Human Rights 566 (Central Law Publications, Allahabad, 21st Ed./ 2016)

[2] Supra note 1 at 566, 567

[3]  Introduction to the study of international law 176 (6th edition)

[4] Supra note 1 at 570

[5] Supra note 1 at 571