A succession of crises has marked the last decade of European integration, leading to disorientation among integration scholars. Older frameworks for understanding have been challenged, while the outlines of new ones are only now beginning to emerge. This book looks to history to provide a more durable explanation of the nature and legitimacy of European governance going forward. Through detailed examination of certain fundamental but often overlooked elements in EU history, Peter Lindseth describes the convergence of European integration around the 'postwar constitutional settlement of administrative governance.' 'Administrative' here does not mean 'non-political' or 'technical'-it means that supranational regulatory authority should properly be seen as 'delegated' from national constitutional bodies. As such, supranational policymaking has relied to a significant degree on forms of oversight by national executives, legislatures, and judiciaries, following models of 'mediated legitimation' first developed in the administrative state and then translated into the European context. These national mechanisms developed specifically to overcome the core disconnect in European integration-between exercises of otherwise autonomous supranational regulatory 'power,' on the one hand, and the persistence of the nation-state as the primary source of democratic and constitutional 'legitimacy' in the European system, on the other. It has been through recourse to the legitimating structures and normative principles of the postwar constitutional settlement, this study shows, that European public law has sought to reconcile 'Europe' and the nation-state for more than fifty years.