Article 64. Emergence of a new peremptory norm of general international law (“jus cogens”)

Abstract

Since it was agreed that the Convention envisages the emergence of new ius cogens under the condition that the international community as a whole accepts the new rules as peremptory (→ Art 53 MN 26), the ILC was bound to consider the legal effects of these new peremptory rules on prior treaties. These prior treaties were legally valid at the time of their conclusion but have not been adapted to the new legal situation. The mere fact that Art 64 operates in a different section than Art 53 is revealing with regard to the function and purpose of Art 64 in contrast to Art 53. Whereas Art 53 stipulates a rigid regime of absolute nullity of the entire treaty in conflict with prior ius cogens, Art 64 is much more forgiving: new ius cogens has no retroactive effect, ie the treaty – or its affected treaty provisions in case of their separability (Art 44 → MN 13) – terminates the very moment the conflict occurs. The reason for Art 64’s mild sanction regime is obvious: the contracting parties did not want to outlaw themselves by acting contrary to fundamental rules of the international community; rather, the treaty is refuted by subsequent legal developments due to the international community’s interest in the conformity of the entire international legal order with ius cogens.