The Nature of Customary International Law

Introduction:

International Law has an aspect that is known as International Customary Law that dwells upon the principles of custom. Along with treaties, recommendations, and principles of law, the custom has been considered as a primary source of law by the International Court of Justice, United Nations, and the member nations. There has been a little variation in opinions as to what rules are contained in Customary International Law, however many governments have accepted that such a principle exists.

In the year 1950, the International Law Commission had listed a few sources as evidence of Customary International Law- treaties, international and national courts, diplomatic correspondence, and practices of various International Organizations.

Elements of Customary International Law

• The two-element Theory

Customs is a legal obligation that has been derived from a settled conduct which creates an explanation that is legitimate; it has been acknowledged in the field of international law that the mere existence of a practice that is consistent would not suffice a rule that is of international law. Such a combination has been referred as the “two-element theory”, for a customary law to arise, there must exist two different elements- one must be that it should follow opinio juris- a belief that it should be reflective of International Law and the other element that it should be in a position of significant state practice.

• State Practice: Objective Element

The material and objective element of customary International Law is the State Practice. State Practice includes ‘constant and uniform usage’. A State Practice must be analyzed by considering the following issues: how long has the custom been observed, what all forms that it may take, what role has it taken in affecting the state’s practices.

Nature

Customary International Law, has found its source through the widespread and consistent practice by the states. If enough states act in such a consistent manner, that arises out of a sense of legal obligation, and that too for a long period of time, a new form or rule of International Law comes into existence. Such Customary International Laws almost always depends upon the consent of the member nations, implicitly or explicitly. Hence, if in theory, a nation-state doesn’t wish to be joined by any rule of International Law, they can vocally object and not legally bind themselves in it. This type of objection raised must be reiterated constantly.

However, there are certain rules that exist, pertaining to Customary International Law that are considered to be very important and vital that they cannot in any manner be contracted or voted out by the states. Such rules that are preemptory are also called as jus cogens norm. Running in a parallel manner to the jus cogens norm are called obligations erga omnes, and they are considered to be very vital and important within the very ambit of the international system that any state could sue some other state for the fulfillment of the obligation that they were committed to.

As opposed to this, the conventional International Law has found its source from various international conventions that establishes certain rules that expressly recognize the rules set forth by the contesting states. For example, the bilateral treaties are sensed to be creating certain obligations that are specific to the states that sign them. Such conventions and treaties, when they are entered between two different states, are almost always binding on the two states, but they do not become a source of International Law. On the other hand, multilateral treaties have the ability to transform into a source of customary International Law, that subsequently becomes binding on all the states in the international system, whether they are the parties to a particular treaty or not if a large number of the non-signatory states from the International System adheres to the provisions that are set forth out of a sense of legal obligation.

Conclusion

State practice and opinion juris has been constantly considered as the accepted source of customary international law, but the past few centuries have seen some concerted movement in the legal scholarship which has engaged to redefine the source of customary international law away from a huge blanket of reliance from these two sources.