A Spatial Model of U.S. Senate Elections

The importance of primaryelections is considered within the contextof U.S. Senate elections where senatorsserve overlapping terms and voters areassumed to balance their two senatorsagainst each other. Voters behavestrategically in the primaries butconvergence to the median position is notachieved except as a knife-edge result.More generally, constraints in the partyspace prevent the party of the sittingsenator from obtaining the median'spreference allowing the opposition party tonominate a candidate further away from themedian while still capturing the medianvoter. Empirical evidence supports thenotion that senate divergence is a functionof the state primary system.