Functions of Jus Cogens

Abstract This chapter explores the functions of jus cogens. The asserted functions of jus cogens are particularly important because the very definition of the term is often stated in relation to the primary function it serves, that is, on its being a norm from which no states can derogate by mutual agreement. A second function is sometimes asserted: that jus cogens imposes a duty on all states to respect such norms and as a consequence any unilateral act in violation of a jus cogens norm would be null and void. There is little state practice or jurisprudence in respect to either function; the actual function appears to be more expressive, being an important though symbolic declaration of societal values. The chapter discusses each of these functions in turn before providing some concluding remarks on jus cogens.