Political parties as a commitment technology: effects of term limits on vote share

Building on models of electoral competition with reputational mechanisms, I show that term limits decrease the vote share of candidates from parties less able to reward or punish candidates. Candidates suffer by not being able to credibly commit to policies far from their own preferences. Assuming that the major parties can provide better discipline of their members than third parties, the implication of the model is that third party candidates will be worse off, in terms of vote share garnered, in elections for offices with term limits. The hypothesis that third parties do worse under term limits is tested using state gubernatorial elections. Data from 1977-2008 show the vote share of third party candidates is approximately six percent lower in elections for a term-limited office when controlling for other election characteristics and regional and temporal trends in party popularity.