International law is a system of rules that governs the conduct and relations of States and their treatment of individuals within State boundaries. It defines the legal responsibilities of States, and regulates global commons such as international waters, outer space and world trade. Its sources are international custom (general state practice accepted as law), treaties, and general principles of law recognised by most national systems.

A prominent approach to the legitimacy of international law is based on consent, whether explicit (opinio juris) or implicit (e.g., by failing to object). This view, however, is incompatible with the principle of sovereign equality recognized in Article 2 of the UN Charter. In addition, it cannot explain the existence of norms that have become jus cogens, peremptory norms of international law from which derogation by treaty is explicitly prohibited.

Another problem with this theory is that it does not account for the fact that there are areas of international law in which states do not consent to its rules at all (e.g., the law on the use of force). Moreover, it is not clear how to distinguish between a claim of consent to a specific rule and a claim of a de jure right to be free from its jurisdiction.

The concept of self-determination has introduced a new dimension to the debate on sovereignty in the context of international law and institutions, allowing people to advance claims to ultimate authority that may challenge the authority of an extant state. This introduces tensions that have long been present in international affairs, and calls into question the assumption of a de jure right to rule.