What Is Customary International Law Definition

Customary international law is an integral part of international law. Customary international law refers to international obligations arising from established international practices, as opposed to obligations under formal written conventions and treaties. Customary international law results from a general and consistent practice of States that follow it in the sense of legal obligation. Two examples of customary international law are the doctrine of non-refoulement and the granting of immunity to visiting heads of State. Customary international law is an aspect of international law that includes the principle of habit. In addition to the general principles of law and treaties, custom is considered by the International Court of Justice, jurists, the United Nations and its member States as one of the main sources of international law. There are different types of customary laws that are recognized by States. Some customary international rights rise to the level of ius cogens by being accepted by the international community as non-derogable rights, while other customary international rights may simply be followed by a small group of States. States are generally bound by customary international law, whether States have codified these laws at the national level or by treaties. With regard to the psychological element, which is opinio juris, the International Court of Justice further stated in the North Sea Continental Shelf case that “the acts in question must not only constitute a settlement practice, but also be carried out, or be carried out in such a way as to provide evidence of the hypothesis that such practice by the existence of a State governed by the rule of law, which it requires, is made compulsory. The States concerned must therefore feel that they are complying with a legal obligation. [16] The Court emphasized the need for a “sense of justice” rather than “acts motivated by considerations of courtesy, convenience or tradition.” [16] This was later confirmed in Nicaragua against the United States of America. [17] The International Court of Justice (ICJ) is the principal judicial organ of the United Nations and settles disagreements between UN Member States.

According to article 38 of Chapter II of the Statute of the International Court of Justice, international customs and the general practices of nations are one of the sources of customary international law of the Court and one of the sources of international law. Customary international law can be established by evidence of (1) State practice and (2) opinio juris. The recognition of various customary rights can range from simple bilateral recognition of customary law to global multilateral recognition. Regional customs may become customary international law in their respective regions, but do not become customary international law for countries outside the region. The existence of bilateral customary law was recognized by the International Court of Justice in the case concerning the right of passage through Indian territory between Portugal and India, in which the Court “found no reason for a long-standing practice between the two States, accepted by them as the regulation of their relations, does not constitute the basis of mutual rights and obligations between the two States”. [18] For more information on customary international law, see this Harvard Law Review article, this University of Virginia Law Review article, and this University of Michigan Journal of International Law article. Other examples that are accepted or claimed as customary international law are the immunity of foreign heads of State and the principle of non-refoulement. The United Nations Security Council adopted the Geneva Conventions as customary international law in 1993 because they have since been transformed into customary international law. If a treaty or law has been designated as customary international law, parties that have not ratified that treaty are required to comply in good faith with its provisions. [19] Customary international law, on the other hand, derives from a “general practice recognized as law.” Such a practice is found in official reports of military operations, but is also reflected in a variety of other official documents, including military manuals, national legislation and case law. The requirement that this practice be “accepted as law” is often referred to as “opinio juris”.

This characteristic distinguishes between practices that are required by law and practices that are pursued, for example, as a matter of policy. A peremptory norm (also jus cogens, Latin for “imperative right”) is a fundamental principle of international law that is accepted by the international community as a norm from which there is never a derogation (not derogable). These norms are rooted in the principles of natural law,[6] and all laws that conflict with them should be considered null and void. [7] Examples include various international crimes; A State violates customary international law by authorizing or participating in slavery, torture, genocide, war of aggression or crimes against humanity. [8] The Statute of the International Court of Justice recognizes the existence of customary international law in Article 38(1)(b), which was incorporated into the Charter of the United Nations by Article 92: “The Court, whose task it is to rule in accordance with international law, like disputes submitted to it, shall apply. international custom, as evidence of a general practice recognized as law. The laws of war, also known as jus in bello, were long a matter of customary law before being codified in the Hague Conventions of 1899 and 1907, the Geneva Conventions and other treaties. However, these conventions do not claim to regulate all legal issues that may arise during a war. Instead, art. 1 para.

2 of Additional Protocol I, according to which customary international law regulates legal questions relating to armed conflict that are not covered by other conventions. [9] [10] “Although a very broad and representative participation in a convention may show that a treaty rule has become a general rule of international law, the number of ratifications and accessions in this case has so far been hardly sufficient […].