Uncontested Primaries: Causes and Consequences

Abstract

Direct primary elections were introduced in the United States to limit the power of parties, to favor entry of new candidates, and to foster competition. However, a majority of incumbents faces no competition in their primary. We propose a formal model of primaries to rationalise this fact and analyse its welfare consequences. The party of the incumbent can influence the challenger's entry cost in the primaries. Primary challengers thus choose strategically to enter only when the incumbent is of low competence. Voters who are poorly informed about the competence of candidates use the competitiveness of the primary to update beliefs. If the party can commit ex-ante to some entry cost, voter beliefs about the party candidate are highest after an uncontested primary. Nevertheless, the party prefers to minimize the entry cost to get a contested primary. This also maximises the welfare of voters. If the party cannot commit, for example because the current incumbent influences its decisions, voter beliefs are not always highest after an uncontested primary. Nevertheless, the party chooses to deter entry into the primary whenever the incumbent is competent enough. In that case, uncontested primaries are inefficient and regulation favoring entry would benefit voters.