In this paper, we propose a unified approach to study participation and voting in multiple elections. The theoretical framework combines an “uncertain-voter” model of turnout with a spatial model of voting behavior. We apply our framework to study turnout and voting in U.S. national (presidential and congressional) elections, and structurally estimate the model using individual-level data for the 2000 elections. The estimated model replicates the patterns of abstention, selective abstention, split-ticket voting, and straight-ticket voting observed in the data. We also quantify the relationships between observed individual characteristics and unobserved citizens’ ideological preferences, information, and civic duty. Finally, we assess the effects of policies that may increase citizens’information and sense of civic duty on their turnout and voting behavior.