What is the marginal effect of competitiveness on the power of electoral incentives? Addressing this question empirically is difficult because challenges to incumbents are endogenous to their behavior in office. To overcome this obstacle, we exploit a unique feature of Kansas courts: 14 districts employ partisan elections to select judges, while 17 employ noncompetitive retention elections. In the latter, therefore, challengers are ruled out. We find judges in partisan systems sentence more severely than those in retention systems. Additional tests attribute this to the incentive effects of potential competition, rather than the selection of more punitive judges in partisan districts.