The Duality of Direct Effect in International Law

This article assesses how, fifty years after the ECJ delivered its judgment in Van Gend and Loos (VGL), the doctrine of direct effect of international law has fared outside the European Union. Against the background of an exceedingly heterogeneous practice, this article argues that the concept of direct effect is characterized by a fundamental duality. Direct effect may function as a powerful sword that courts can use to pierce the boundary of the national legal order and protect individual rights where national law falls short. But more often than not, the conditions of direct effect legitimize the non-application of international law and shield the national legal order from international law. International law provides support for both functions. But above all, it defers the choice between these functions to national courts. The practice of direct effect of international law exposes how national courts play a critical political function at the intersection of legal orders.