The Emergence of Parties: An AgentBased Simulation

An agent-based computer simulation demonstrates that results from Downs, Duverger, Riker, and Sundquist can be seen as emergent consequences of five simple rules about iteratively forming coalitions and adjusting policy platforms. The model creates distributions of agents who form coalitions within a political body. By modifying and omitting the basic rules, I compare results from plurality and majority-seeking actors and from policy-seeking, office-seeking, and mixed-strategy coalitions. A set of simple rules implemented by agents with extremely bounded knowledge are sufficient to drive the classic median voter, two-party system, minimum winning coalitions, and party realignment results in a single framework.