Why Primaries? The Party’s Tradeoff between Policy and Valence∗

We elaborate a theory to explain why and when political parties choose to hold primary elections. Party leaders face a trade-off between primary elections and elite-centered selections. The benefit of a primary is revealing the campaigning skills of candidates. Its cost is the ideological extremism that primary voters might induce on candidates. We find that primary elections are more likely when the party leadership and the potential primary voters are ideologically similar (which is consistent with the recent empirical research by Meinke, Staton and Wuhs (2006)). Intriguingly, our model predicts that parties with extremist ideologies are more likely to be internally democratic. For intermediate values in the parameters, parties have multiple equilibria in their decision to adopt primaries or not. And finally, parties display a significant degree of contagion, meaning that a party’s adoption of a primary will influence the other party to adopt a primary as well. ∗This paper benefitted from being presented at Nuffield College in October 2007, the annual meeting of the American Political Science Association in September 2007, and Harvard University in April 2007. I thank Christopher Avery, Robert Bates, Indridi Indridason, John Patty, Brian Richardson, Kenneth Shepsle and James Snyder for their insightful comments. I also thank the Institute of Quantitative Social Sciences for its financial support. All remaining errors are my own. †Postdoctoral Prize Research Fellow at Nuffield College in Oxford University, [email protected] .