Custom in General International Law and International Criminal Law: A Survey of Selected Issues

This article surveys selected decisions of international criminal courts and tribunals, and related literature, examining custom from a general standpoint. This article considers the place and nature of custom, with a particular focus on challenges levelled against custom's suitability in international criminal law. This article also analyses custom's 'structure', and, more specifically, the application of the 'two-element approach' by international criminal courts and tribunals. This articles then discusses claims that international criminal courts and tribunals engage in sui generis customary law-making, and revisits the distinction between custom in foro and in pays, examining that distinction's pertinence to assessing such claims. Having emphasised the influence of general international law on international criminal law, this article lastly reverses its focus, and addresses custom's wider functions as source for rules on custom's identification and, more generally, other sources' recognition, showing how some decisions of international criminal courts and tribunals elucidate those wider functions.