What are the sources of international law

7.1.3 Legal Sources of International Law

There is no “international legislator” who could authoritatively determine the content of international law; rather, international law is created by the subjects of international law themselves. Article 38 (1) of the Statute of the International Court of Justice lists the permitted types of norm generation, the formal legal sources of international law:

"The Court of Justice, whose task it is to decide the disputes brought before it in accordance with international law, applies

a. international agreements of a general or special nature, in which rules expressly recognized by the conflicting states are laid down;

b. customary international law as the expression of a common practice recognized as law;

c. the general legal principles recognized by the civilized peoples;

d. Subject to Article 59, judicial decisions and the doctrine of the most capable international lawyers of the various nations as an aid to establishing legal norms. "

The term referred to in letter a "International Agreements" is to be equated with "contracts". International law treaties, like private law treaties, arise from mutually related, consistent declarations of intent by the contracting parties with the will to be legally binding and can be concluded both bilaterally and multilaterally.

"International Customs Law" (Letter b) is unwritten international law, which comes about through the consistent legal convictions of the subjects of international law and the general practice, i.e. the actual compliance with this legal conviction by the legal counterparts.

Both general principles of law (lit. c) are material principles of law, the source of which is controversial. A common thesis is that it is a matter of the material or formal principles to be determined by (evaluative) comparative law, which apply consistently in the law of the "civilized peoples" and are suitable for transfer to international law (Vitzthum 2007, p. 72). Examples are good faith or self-defense / emergency aid.

The in lit.d. cited judicial decisions and doctrines of the most capable international law scholars on the other hand do not form legal sources, but rather "aids for establishing legal norms", that is Sources of legal knowledge.