Trashing Customary International Law

Abstract

Central to the World Court’s mission is the determination of international custom “as evidence of a general practice accepted as law.” Students of the Court’s jurisprudence have long been aware that the Court has been better at applying customary law than defining it. Yet until Nicaragua v. United States, little harm was done. For in the sharply contested cases prior to Nicaragua, the Court managed to elicit commonalities in argumentative structure that gravitated its rulings toward the customary norms implicit in state practice. The Court’s lack of theoretical explicitness simply meant that a career opportunity arose for some observers like me to attempt to supply the missing theory of custom.