Part I Introduction, Ch.7 Changing Jus Cogens Through State Practice? The Case of the Prohibition of the Use of Force and its Exceptions

Subject(s):

Vienna Convention on the Law of Treaties — UN Charter — Peremptory norms / ius cogens — Opinio juris — Customary international law — Jurisdiction

This chapter examines how international law treats state practice on the actual or claimed exceptions to and derogations from the peremptory prohibition of the use of force. It looks at attempts to fragment or alter the content of Article 2(4) of the UN Charter which prohibits the use of force, from the Cold War period to the post-Cold-War period. The discussion begins by assessing the nature and relevance of state practice before turning to the rules of jus cogens and the way in which they interact with state practice. More specifically, the chapter analyses the question of whether the conflict between state practice and jus cogens goes to derogation from, or modification of, jus cogens norms. Finally, it considers the argument against the jus cogens status of the prohibition of the use of force and the implications of the strict requirement of uniformity inherent in jus cogens and its non-derogability.