Effective Parties in a Model of Repeated Legislative Bargaining.

A self-enforcing equilibrium account of legislative party organization in the context of the standard legislative bargaining model demonstrates how a member of a party would overcome the temptations to violate a party's agreement to stick together on legislative matters in the absence of external enforcement. The model is robust, and realistic, in the sense that departures from the equilibrium path lead eventually to restablishment of intra-party cooperation. Thus we construe legislative politics in a way that would support either a purely preference-based equilibrium or a equilibrium in which the legislature has an internal system of party organization that influences members sometimes to vote indifferently than they would based on their myopic issue preferences alone.