Introduction
Much has been written about the ground-breaking decisions taken by the Court of Justice of the European Union (CJEU) in the 1960s and 1970s and their impact on the evolution of the European Union’s (EU’s) legal order. There is no doubt that the CJEU’s doctrinal innovations in those early years of European integration at least partly “constitutionalized" the founding treaties by empowering individuals with European rights they could vindicate in front of domestic courts against conflicting domestic law, and consequently by bestowing on itself powers akin to judicial review. The cases in which the CJEU introduced and developed the relevant doctrines of direct effect and supremacy since van Gend en Loos 1 and Costa v ENEL 2 figure prominently in every textbook. Their interpretation and scholarly reconstruction are vast and include as much praise as criticism. Given the unprecedented curtailment of national sovereignty implied by these doctrines, much research has also been devoted to understanding why member states acquiesced.
