Free Essay: The Laws, Rules, and Principles Governing the Use of Force under International Law

Since time immemorial, societies have resorted to the use of force against others that threatened their sovereignty, peace, and security. Force was also used even before the concept of nation states came into being to wage war against those considered enemies, to plunder, and to explore new lands. However, with the formation of the nation-state and the recognition of just how destructive or devastating the use of force can be as demonstrated during the two world wars, international law which governs the relations between states has put some restrictions and prohibitions on the unilateral use of force by states. As a matter of fact, the prohibition of the use of force is now considered one of the most basic and important principles of customary international law. This customary rule of international law has also been enshrined in the Charter of the United Nations or the UN Charter, Article 2(4) of which prohibits the threat or use of force against any other member state without a tacit authorization of the UN Security Council (UNSC).

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Moreover, the prohibition on the use of force has crystallized into a peremptory norm or a jus cogens principle from which no state is allowed to depart (Petreski 2). However, faced with contemporary security threats or challenges mainly from terrorist organizations, states rarely comply with this prohibition against the use of force - sometimes for good reasons. A recent example is the combined use of military force against Syria by the US and UK in April 2018 without UNSC approval. This paper is organized into three main sections. The first part discusses a brief history of the issue of the use of force under international law while the second part examines the current status of use of force and the applicable rules, laws, legal principles, and exceptions under international law. The last section analyzes whether and the extent to which the subjects of international law comply with the law on the prohibition of the use of force. The paper advances the argument that even though international law prohibits the use of force by states, various socio-political factors and incidents have prompted states to disregard this restriction. It also argues that the current law on the legality of the use of force is unclear, ambiguous, or less developed judicially thus leading to limited compliance by states.

Historical Background on the Use of Force under Public International Law

In their international relations, states have for centuries resorted to using of force in the achievement of specific desired aims, such as preservation of their political independence or territorial integrity and repulsion or in response to an armed attack from another state. Hence, before the current international legal order came into being, the use of force as a means of settling disputes between states was acceptable. In the early centuries, a resource to use of force during inter-state wars was also justified by the jus ad bellum (right to war) doctrine.

According to Arend and Beck, the history of the law on the use of force may be divided into six historical periods including the "just war period, the positivist period, the League of Nations period, the Kellog-Briand Pact period, the United Nations Charter period, and the post-UN Charter period" (11). The right to use force particularly during inter-state wars goes back to the Roman law of war and peace. As more independent states emerged particularly in Europe, the doctrine of just war previously coined by early theologians like St. Thomas Aquinas and St. Augustine became a justification for use of force to settle disputes. The establishment of the system of balance of power under the Peace of Westphalia in 1648 and the emergence of legal positivism advocating for state sovereignty also made the use of force to be considered normal among states. During these periods in the history of international law, states used the concepts of reprisal and self-defense to justify the use of force against other states (Arend & Beck 18).

However, in the twentieth century with the outbreak and aftermath of the two world wars, states changed their attitudes towards the use of force. The establishment of the League of Nations in 1919 under the Treaty of Versailles was meant to deter future acts of aggression and use of force following the destructive First World War. Another attempt to prohibit the use of force during this period was the signing in 1928 of the Kellog-Briand Pact, a treaty providing for the denunciation of war and regulating the right of states to go to war. The treaty did not, however, renounce the use of force by states as it only prohibited recourse to war. It was the outbreak of yet another bloody world war in 1939 (WWII) which reaffirmed the need for a stronger legal framework to govern the use of force by states during wars. Aware of the destruction caused by the use of force during WWII, states came together in San Francisco, CA in 1945 to adopt the Charter of the United Nations to provide a stronger legal framework to regulate the use of force by states and to further foster peaceful relations among members of the international community.

The Current Status of Use of Force: The Applicable Laws, Rules, and Legal Principles

The contemporary laws, rules, and legal principles pertaining to the use of force under international law are found in the sources of public international law. According to the Statute of the International Court of Justice at Article 38 (1), the main sources of international law are judicial decisions and scholarly writings or treatises, general principles of law, customary international law, and treaties or conventions between states. Treaties are the main source of international and refer to negotiated instruments and agreement among states on particular issues such as trade, peace, human rights, and use of force. The general legal principle is that all states that are a signatory to a treaty are bound by the terms of the treaty and hence any violation of the terms represents a violation of international law and makes the state liable.

The UN Charter and Use of Force

Regarding the use of force, the main treaty is the Charter of the United Nations (UN Charter). This treaty binds all states that are members of the United Nations as an international organization. Almost all states are members of the UN and are hence bound by this international convention. When it comes to the legality of the use of force, the relevant provision of the UN Charter is Article 2 (4) which provides that in their international relations, all members of the UN must refrain from the threat or use of force against other states' political independence or territorial integrity. Under Clause 7 of this Article, states are directed not to intervene in the domestic affairs of other states and are instead urged to submit any disputes to be settled under the UN Charter.

Further, according to Article 41 of the Charter, however, the UN Security Council has the power to decide the measures involving the use of force that can be employed by members. Moreover, Article 42 of the UN Charter gives the Security Council the power to use land, sea, or air force as is necessary for the maintenance or restoration of international peace and security when the measures taken by states under Article 41 are found to be inadequate to do so. This prohibition on the use of force under Article 2 (4) UN Charter is mainly in tandem with the primary purpose of the UN provided under Article`1(1) which is the maintenance of international peace and security. The unjustified use of force by states may undermine international peace and security.

The Self-Defense Exception to Use of Force Prohibition

However, Article 51 of the UN Charter seems to give states the inherent right of individual or collective self-defense when attacked by another state. The upshot of this provision is that members of the UN are permitted to use the force necessary to defend themselves from external aggression where necessary measures to maintain and restore peace and security have not been taken by the UN Security Council. As held in the Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion (1994), for self-defense under Article 51 of the Charter to be used by a state as an exception to and a justification for the use of force against another state, the measures of self-defense must be proportionate to the armed attack and the measures have to be necessary in response to the attack.

This notwithstanding, however, Lewis argues that there seems to be a general lack of elucidation or clarification and ambiguities under Article 51 regarding the content, parameters, and scope of the right of states to use force as a form of self-defense (5). As a consequence, there is lack of uniformity in the approach that states have taken regarding the prohibition on the use of force under Article 2(4) of the Charter. The use of the words "inherent right" under Article 51 of the Charter even complicates things further because it conflicts with established customary rules of international law on the restrictions on the use of armed force. The scope of this right of self-defense as an exception to the prohibition on the use of force thus remains ambiguous or unclear and hence is open to abuse by states.

Further, it is not clear what the term "armed attack" under Article 51 of the Charter actually refers to and whether it also binds non-member states of the UN. It raises the issues of response to an armed attack, nature of an armed attack, and who has to carry out the armed attack for the inherent right to self-defense to become exercisable by states. The other UN instruments that contain the prohibition on the use of force by states include the 1970 Declaration on the Principles of International Law Concerning Friendly Relations and Cooperation among States and the 1987 Declaration on the Enhancement of the Effectiveness of the Principle of Refraining from the Threat or Use of Force in International Relations.

Customary International Law and Use of Force

A customary international law is a source of international law derived from state practice and opinio juris. It is based on those customs, norms, rules, or principles that have crystallized into customary law and are followed by states even though they are unwritten. According to Lewis, the prohibition on the use of force as provided for under Article 2(4) of the UN Charter has become a rule of customary international law and gained the jus cogens status (5). Due to the devastating impacts of the use of deadly force on other states, states generally tend to abide by the prohibition on the use of force - or at least give justifications whenever they have to use force- because they believe it is necessary for the maintenance of international law, order, peace, and security. Hence, according to Peters, for any state to attempt to modify this customary rule of international law as the US has so done by advocating for pre-emptive self-defense, such modification has to meet the elements of opinio juris and state practice (n.p.).

General Principles of Law and Judicial Decisions on Use of Force

General principles of law as a source of international law refers to those rules and principles of law that are widely accepted under both domestic and international legal systems. An example of such a principle is the principle of legal personality of corporations or the principle of non-refoulement of refugees.

Judicial decisions are mainly those of the International Court of Justice (ICJ) which has exclusive jurisdiction to hear and determine disputes arising between states.