Veto player approaches have come to occupy a central role in comparative politics. This article critically reviews the literature, focussing especially on veto player explanations of policy outputs and outcomes. The review highlights three problems empirical veto player studies have to face: 1) identifying the relevant veto players, 2) establishing equivalence between veto players, and 3) specifying (theoretically or empirically) veto players' policy preferences. The article concludes that empirical veto player analyses advance our understanding of political institutions and their effects, but that they should deal more systematically with the three above mentioned problems.
Keywords: veto players, veto points, comparative public policy, intentional explanation
Introduction
1Veto point and veto player approaches have come to occupy a central place in comparative politics, especially in the fields of comparative public policy and political economy. Virtually every policy area has been studied within at least one of the various approaches, and the relevant literature grows at a fast pace. The most elaborate and prominent approach, George Tsebelis' veto player theory (Tsebelis 1995a;, moves well beyond the explanation of particular policy outputs or economic outcomes and tries to provide a unified theoretical 1 This article grew out of a paper presented at the conference "The consequences of political institutions in Democracy", Duke University, Department of Political Science, April 5-7, 2002. In addition to the conference participants, I wish to thank Thomas Bräuninger, André Kaiser, Bernhard Kittel, Matthias L. Maier and Uwe Wagschal for helpful comments and discussions. Special thanks to Herbert Kitschelt and Fritz W. Scharpf for discussions and encouragement. All remaining errors are mine.2 STEFFEN GANGHOF perspective on political institutions in a wide variety of political systems. Tsebelis' theory systematically relates veto players to the potential for policy change in a political system, which is in turn linked to important system characteristics such as regime stability, government stability or bureaucratic independence. Tsebelis' theory can thus be seen as the main (theoretically based) competitor to Lijphart's (empirically based) distinction between majoritarian and consensus democracy (Lijphart 1999).This article has three related goals. First, I want to review the recent literature on veto points and veto players, focusing especially on explanations of policy outputs and economic outcomes. In doing this, I will for the sake of simplicity use "veto player approaches" as a general label for studies that highlight the importance of institutional veto power and refer to Tsebelis' work as veto player theory. Given the volume of the relevant literature, my aim is not to enumerate each and every veto player (hereafter: VP) study but to give the reader an idea of how this literature has developed. This point leads me to my second goal. While different VP approaches are often perceived as being close ...