The achievements of the European Court of Justice in instilling the rule of law within the domain of economic integration is to witness to what extent public international law can be dynamic. For the Court of Justice, which attempted to slip its international law origins by characterizing European Community law as belonging to a ‘new legal order’; the post-Maastricht era has been a rude awakening. So effective was the European Court, during its first four decades, that Community law was seen as being set apart from traditional international law; as being sui generis. However, with the Maastricht Treaty and again with the Amsterdam Treaty, it has become evident that the creation of what is today termed the ‘European Union’ is governed by international law and that, ultimately, it is the States and not the European institutions – foremost among them the Court of Justice – which are the ‘Herren der Verträge’.Yet, within the domain of economic integration, the European Court has acted in a truly revolutionary manner for an international court. Barring witness to the achievements of the Luxembourg Court in this domain is to realize to what extent international law can be moulded to achieve results. The lesson to be learnt from the function of the European Court within the field of economic integration is that if there is State consensus, an international court can promote and actively ensure the rule of law. While the uniqueness of the European experience and that of the European Court of Justice may not be able to be grafted onto other areas of the international relations, what the evolution of the European Court does provide is a new way of thinking about international law. The supranational elements, those ‘constitutional’ areas of European law demonstrate the avenues that public international law can travel, if States are willing to allow it.