Peremptory norm

A peremptory norm (also called jus cogens) is a fundamental rule of international law that is accepted and recognized by the international community of states as a whole as a norm from which no derogation is permitted. Unlike ordinary treaty obligations or customary international law, a peremptory norm cannot be overridden by treaties, agreements, or national laws. Thought to be so fundamental that it even invalidates rules drawn from treaty or custom, "norms of this character, therefore, cannot be derogated from by the will of the contracting parties." There is no universal agreement regarding precisely which norms are jus cogens nor how a norm reaches that status, but it is generally accepted that jus cogens bans genocide, maritime piracy, enslaving in general (i.e. slavery as well as slave trade), wars of aggression and territorial aggrandizement, and generally as well torture, and refoulement.