Equilibrium Refinement in Dynamic Voting Games

We propose two related equilibrium re…nements for voting and agenda-setting games, Sequentially Weakly Undominated Equilibrium (SWUE) and Markov Trembling Hand Perfect Equilibrium (MTHPE), and show how these equilibrium concepts eliminate non-intuitive equilibria that arise naturally in dynamic voting games and games in which random or deterministic sequences of agenda-setters make o¤ers to several players. We establish existence of these equilibria in …nite and in…nite (for MTHPE) games, provide a characterization of the structure of equilibria, and clarify the relationship between the two concepts. Finally, we show how these concepts can be applied in a dynamic model of endogenous club formation. Keywords: voting, agenda-setting games, Markov trembling-hand perfect equilibrium. JEL Classi…cation: D72, C73. Daron Acemoglu gratefully acknowledges …nancial support from the National Science Foundation.