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International Law: Sources of Law

Create from Seton Hall Law Guide located at:

State Practice (National and Foreign Law)

State Practice in the International Law context refers to the practices followed by a state's sense of legal obligation. The International Court of Justice's website states that "The Court's decisions show that a State which relies on an alleged international custom practiced by States must, generally speaking, demonstrate to the Court's satisfaction that this custom has become so established as to be legally binding on the other party."

Custom and Other Principles

Customary international law (CIL), also called "international custom," is an important part of international law. It consists of "a uniform and consistent practice in relationship between nations that serves as evidence of a generally accepted law." [Black's Law Dictionary, 10th ed.]. Customary international law is considered binding, but whether a particular practice rises to the level of CIL is often hotly disputed. 

Customary international can be hard to research. And there is no single research strategy. Throughout your research, watch for synonyms and related concepts. Emerging CIL principles are prone to changes in terminology; e.g., humanitarian intervention was briefly known as the Annan Doctrine, but is now often called "responsibility to protect" or "R2P."

Some useful sources to gain an understanding of CIL held by Rodino are listed below. 

Continue Your Research