Primary election systems and representation

We examine how differences in the institutions that regulate candidate nomination procedures, specifically direct primary election laws, affect the types of candidates elected in nonpresidential American elections. We hypothesize that in more closed primary systems, control over candidate nominations by ideological extremists will translate into a higher likelihood that extreme candidates win in the general election. We hypothesize that in more open systems, participation by a wider spectrum of the electorate means that candidates must appeal to more moderate voters, leading to the election of more moderate candidates. Using pooled cross-section time-series regression analysis, we find that U.S. representatives from states with closed primaries take policy positions that are furthest from their district's estimated median voter's ideal positions. Representatives from states with semi-closed primaries are the most moderate. We conclude that the costs of strategic behavior created by electoral institutions have important consequences for electoral outcomes.