This paper presents a model of elections that explores the relationship between incumbent upsets and incumbents running unopposed. A valence-disadvantaged candidate (a potential challenger), who possesses private information about the extent of this disadvantage, first decides whether to challenge a valence-advantaged candidate (the incumbent). If the election is contested, the two candidates engage in policy competition. In equilibrium, the incumbent is never certain of the strength of a challenger she faces, and she may risk losing by proposing a less moderate policy for the possibility of winning at a policy more to her liking. The model demonstrates that analysts risk mischaracterizing candidate behavior by ignoring the possibility that an advantaged candidate may lose due to “rational complacency.” Key comparative statics may switch signs if analyses exclude uncontested elections, and reducing the frequency of uncontested elections entails the trade-off for voter welfare of more extreme platforms in contested elections.

本文提出了一个选举模型，该模型探讨了现任up难与无反对派现任议员之间的关系。具有劣势程度的私有信息的价弱者（潜在的挑战者）首先决定是否挑战价弱者（现任者）。如果选举有争议，则两名候选人将参与政策竞争。在平衡状态下，任职者永远无法确定自己所面对的挑战者的实力，而且她可能会因提出较温和的策略而提出不太温和的策略，而可能面临输家的风险。该模型表明，分析人员忽略了因“理性自满”而处于优势地位的候选人可能会失去的可能性，从而冒着误导候选人行为的风险。