A peremptory norm 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."