European legal integration, provoked by the European Court of Justice (ECJ) and sustained by private litigants and national judges, has gradually but inexorably “transformed” (Weiler 1991) the European Community (EC). The “constitutionalization of the treaty system” not only displaced the traditional, state-centric, “international regime” of the diplomat and the international relations scholar (Stein 1981 ; Weiler 1981 ; Burley and Mattli 1993 ; Stone 1994). It has progressively enhanced the supranational elements of the EC, while undermining its intergovernmental aspects, federalizing the polity in all but name (Lenaerts 1990). And it has altered, within a very wide zone in Western Europe, how individuals and firms pursue their interests, how judges resolve disputes, and how policy is made at both the national and supranational levels of government (Stone Sweet and Brunell 1998a). Today, the ECJ has no rival as the most effective supranational judicial body in the history of the world, comparing favorably with the most powerful constitutional courts anywhere.
Formerly the purview of specialists, interdisciplinary research on the European legal system has exploded into prominence. Law journals, once concerned exclusively with national law, now routinely document the creeping reach of EC law into formerly autonomous domains. Journals devoted to European law and the ECJ have appeared, 1 and new treatises and perspectives on the Court's burgeoning case law are proliferating (Craig and De Burca (eds.) 1999 ; Craig and De Burca 2003). In the past decade, American political scientists, including those working in the fields of international relations, comparative politics, and law and courts, have published more articles on the ECJ than they have on any other court, excepting the US Supreme Court. Recent dissertations (also Nyikos 2000 ; Cichowski 2002) have begat new books (Alter 2001 ; Conant 2002), and the field of judicial politics in the EU is regularly surveyed (e.g. Mattli and