This dissertation investigates the relationship between elections and legislators’ behavior in democracies, focusing on the U.S. House of Representatives. The first chapter examines how electoral incentives influence representatives’ legislative activity and policy positions. Compiling data from 1954 to 2022, I compare legislators who win primaries and remain motivated for reelection to those who lose and exit the race. Through regression discontinuity and difference-in-differences designs, I find that primary losers significantly reduce effort-related activities, as evidenced by decreased roll-call participation, bill sponsorship, and voter communication. In contrast, the results show that legislators do not adjust policy positions for reelection; both winners and losers maintain consistent ideological and party-line adherence. These findings illuminate the scope of electoral incentives' effects and contribute to debates on electoral accountability and democratic representation. The second chapter explores how legislators respond to challengers of varying quality. Existing theories offer differing predictions about how incumbents behave under competitive pressure, yet, it remains empirically difficult to isolate legislators’ responses to challenger quality. This chapter addresses that challenge by leveraging the quasi-random variation in challenger quality produced by close opposition party primaries. The findings suggest that incumbents’ behavioral adjustments are limited, offering important implications for theories of electoral competition and candidate responsiveness. The final chapter investigates whether the ideological orientation of individual House members varies with their expected level of electoral competitiveness. We find that some—but not all—legislators anticipating closer elections engage in more partisan roll-call voting compared to those in safer districts. Our analysis shows that this responsiveness is more pronounced in districts where voters have greater access to local political information. These findings underscore that electoral accountability depends not only on the presence of competition but also on the quality of the information environment that links representatives to their constituents.