When the Commission and the ECJ embarked on a crusade to strengthen EU enforcement in the early 1990s, they did so for a clear and identifiable reason. This reason was the European internal market and the compliance problems that threatened the realization of this project. In this chapter, I provide the framing necessary for comprehending the supranational institutions’ efforts to strengthen EU enforcement, to be analyzed later in Chapters 4-6. Expressed in the terms of the P-S-A model, the process delineated in this chapter can be described as that of member state agents increasingly attempting to cut loose, as the internal market program raised the costs of compliance and the gains of non-compliance.