Custom on a Sliding Scale

Abstract

Every student who has ever taken a traditional international law course has learned Manley Hudson’s four elements for the emergence of a rule of customary international law: (a)concordant practice by a number of States with reference to a type of situation falling within the domain of international relations;(b)continuation or repetition of the practice over a considerable period of time;(c)conception that the practice is required by, or consistent with, prevailing international law; and(d)general acquiescence in the practice by other States.