What is a source of law and what is it for? What are the sources of international law? Why are they source of law? Why are they binding/not binding? Is there formal hierarchy among the sources of international law? What is Jus Cogens/ peremptory norms of international law? Is it possible a state rely on national law in the context of international court?

Answer?1. Sumber HukumMateriil: bahan-bahan/materi yang membentuk atau melahirkan kaidah atau norma yang mempunyai kekuatan mengikat; dan menjadi acuan bagi terjadinya sebuah perbuatan hukum.

Formal: menentukan prosedur pembuatan hukum (siapa, bagaimana), dan bagaimana hukum materiil ditegakkan.

2. Sumber HK. InternasionalArticle 38 (1) of the ICJ StatuteThe Court, whose function is to decide in accordance with international law such disputes as are submitted to it, shall apply:a. International Convention, whether general or particular, establishing rules expressly recognized by the contesting states;b. International Custom, as evidence of a general practice accepted as law;c. The General Principles of law recognized by civilized nations;d. Subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.

4. Jus Cogens: Psl. 53 VCLT (1969), norma hukum yang tidak dapat diubah.