Gatekeeping Christophe Crombez University of Leuven Tim Groseclose University of California Los Angeles Keith Krehbiel Stanford University Collective choice bodies throughout the world use a diverse array of codified rules that determine who may exercise procedural rights, and in what order. This paper analyzes several two-stage decision-making models, focusing on one in whichthe first-moving actorhas a unique, unilateral, procedural right to enforce the status quo, i.e., to exer- cise gatekeeping. Normative analysisusing Pareto-dominance criteria reveals that the institution of gatekeeping is inferior to another institutional arrangement within this framework-namely, one in whichthe sameactoris given a traditional vetoinstead of a gatekeeping right. The analytical results raise an empirical puzzle: when and why would self-organizing collective choice bodies adoptgatekeeping institutions? A qualitative survey of governmental institutions suggests that-contrary to an entrenched modeling normwithin politicalscience-empirical instances of codified gatekeeping rights are rareor nonexistent. large portion of the procedural complexity in collective choice bodies throughout the world can be characterized in simple game-theoretic models. All that is required as a first-order approxi- mation is to specify analytically features such as unique proposal or veto rights, rules governing amendments, and the order in which decision makers act. Empirical counterparts for these abstractions are plentiful. Examples of individuals or groups who possess unique procedural rights include standing committees in legislatures, the Commission in the European Union (EU), prime ministersin parliamen- tary governments, and the chief executive in presi- dential systems. Examples of their special rights include, respectively, bill referrals as stipulated by jurisdictional arrangements, proposal rights as desig- nated by international treaties, rights to call elections as provided for by nationalconstitutions, and the right to veto legislation after its passage as specified in the many state and national constitutions. Rules govern- ing amendments may, likewise, give opportunities for some-but not all-decision makers to propose mod- ifications to the measure beforethe body.Finally, rules that determine the order in which playersengage in collective choice have force within governments at both intrabranch and interbranch levels.For example, many legislatures haverulesor precedents that require that, upon its introduction, legislation is immediately referred to a standing committee, only to be consid- ered later, if at all, by the full body.Similarly, some sep- aration of powers systems require that the legislative branch initiates policy, but that the executivebranch (e.g., the president) acts next and must sign or veto the proposed legislation. Parliamentary systems may also grant proposalrights to extralegislative bodies or players, such as cabinet ministers. This study presents comparative institutional analyses for a class of simple two-stage decision- making arrangements. Within this class, the focal institutional arrangement is that of gatekeeping. A gatekeeping institutionis a collective choice process in which the first-stage player has a procedural right to implement unilaterally an exogenous status quo policy, in which case the second-stage player is denied the opportunity to participate in collective choice. This basic model has been used to study a wide range of political behavior since Denzau and Mackay (1983) first formalized it. The study has four parts: a discussion of the concept of gatekeeping and associated claims in the literature, focusing on the institutions of the United States and the European Union; a formal analysis of gatekeeping alongside a closely related model of a tra- ditional veto; a descriptive survey of collectivechoice The Journal of Politics, Vol. 68, No. 2, May 2006, Pp. 322-334 @ 2006 Southern PoliticalScienceAssociation ISSN 0022-3816 322