The Definition of ‘Norm Conflict’ in International Law and Legal Theory (EJIL, Oxford University Press)

This article argues that the narrow definition of conflict apparently prevailing in international law doctrine and recent WTO rulings is inappropriate in terms of legal theory and in view of the fundamental structures of the international legal order. The problem with this strict definition is that it does not recognize that a permissive norm may conflict with a prescriptive norm. In this perspective, established conflict rules such as the lex posterior and lex specialis principles cannot be applied in order to determine whether a permissive norm (such as a WTO exception or an MEA permission to restrict trade) actually constitutes the lex posterior or the lex specialis which was meant to prevail by the contracting parties. Further problems in recent academic writings and WTO jurisprudence have been caused by an insufficient distinction between norms of conduct and norms establishing competences. This paper therefore shows that an adequate definition has to encompass incompatibilities between prescriptive norms as well as permissive norms and concludes that an appropriate definition should rely on the ‘test of violation’ first introduced by Kelsen.