Around the world, courts with the power to declare legislative and executive actions unconstitutional are playing a more and more prominent role. Establishing a constitutional court to act as the guardian of the constitution is often seen as a necessary part of making a transition to democracy (Howard 1993; Schwartz 2000; Widner 2001). Thus, in one of the most sweeping waves of democratic transition in history, each of the newly democratic states in Eastern Europe chose to include judicial review in its new constitutional order (Elster, Offe, and Preuss 1998:102). Nor is the influence of courts limited to new democracies. In countries where constitutional review has been a part of the political process for decades, courts appear to be playing a more and more active role (e.g., Shapiro and Stone 1994, 2002; Stone Sweet 2000). The reach of courts extends even beyond the nation-state. Supranational courts like the ECJ that can rule on the validity of national legislation are growing increasingly influential (Alter 2001; Mattli and Slaughter 1998; Stone Sweet and Brunell 1998). It is perhaps not surprising that scholars have begun to speak of a “globalization of judicial power” (Tate and Valinder 1995) and a “judicialization of politics” (Stone Sweet 2000).

Given these trends, understanding how courts interact with legislative majorities and other institutions of governance is of central importance in understanding politics in constitutional democracies today. And yet, comparative political scientists have traditionally devoted surprisingly little attention to studying courts.