In the vast majority of American states, governors have unrestricted authority to fill Senate vacancies, and in an average decade, one-third of all Americans have been represented by an appointed senator. Despite the importance of Senate appointments both theoretically and substantively, no published study has investigated the dynamics of gubernatorial selection. In this paper, we compile an original data set of Senate appointees as well as the list of the candidates the governor considered but did not select. We model the governor’s selection and discover that despite having no formal constraints on their appointment power, governors behave as constrained actors. In particular, we find that governors eschew the potential appointees who are closest to their policy views and instead appoint the candidate who is closest to the ideological position of the voters in their state. This effect is particularly pronounced when the governor is eligible for reelection within two years. These findings have both theoretical and normative implications for understanding Senate appointments, gubernatorial decision making, and the implicit power of the electorate.