ABSTRACT
This chapter explores the status and function of customary international law in the light of the shift from a Europe-centred international law to a global approach which has taken place especially after 1945. Facing the abundance of legal writing on the question of the theoretical basis of customary law and the considerable difficulties involved in arriving at coherent and generally acceptable answers one hesitates to enter into the discussion. The Anglo-American tradition has underlined the importance of customary law whereas, for example the socialist countries have regarded treaty law as the primary source of international law. The formation and evidence of customary law is facilitated by the impressive amount of treaty law which already exists, the development of the “quasi-legislative” functions of the UN General Assembly and other similar bodies, and so forth. The customary law sometimes emerges more rapidly than treaty law.
