Objectives. In choosing candidates to support in congressional elections, voters consider both policy and nonpolicy factors. However, the relative importance of incumbency or presidential approval versus candidates' ideological platforms likely varies across elections. Specifically, stiffer electoral competition should encourage ideology-based voting because candidate information is more plentiful. In contrast, incumbents' ability to garner votes simply by virtue of already holding office should depress proximity voting in elections with incumbents.

Methods. Using data from the 1988–1992 Pooled Senate Election Study, I estimate logistic regression models of individual vote choice.

Results. I find that open-seat elections do promote the use of candidate ideological proximity in the voting calculus but that the effects of election competitiveness are less clear.

Conclusions. The findings have important implications for normative democratic theory, for our constitutional framework, and for elite behavior and aggregate-level electoral outcomes.