Many spatial models of voting suggest that citizens are more likely to abstain when they feel indifferent toward the candidates or alienated from them. In presidential elections, previous research offers evidence that alienation and indifference affect individuals' probabilities of voting. We find evidence that indifference and alienation also affect the decision to vote in midterm Senate elections, a context not previously explored. These individual-level effects imply that candidates' ideological locations should influence aggregate turnout by affecting the proportions of citizens who feel indifferent toward or alienated from the candidates. Our aggregate-level analysis supports this (at least in contests featuring two previous and/or future members of Congress). Our findings underscore the importance of the electoral context for understanding citizen behavior and suggest that elections featuring at least one centrist candidate may be normatively appealing since they stimulate participation.