When will partisans cross party lines to elect a potentially better-performing opposition politician? Individuals in developing countries vote for politicians in expectation of public goods. Partisan geography influences voters’ beliefs about politicians’ ability to exclude them from such goods. Since voters believe they are better able to replace poorly performing incumbents in competitive districts, partisans in non-segregated, competitive constituencies are more likely to vote for opposition candidates than those in other settings. Using a conjoint experiment administered to voters that randomized the characteristics of parliamentary candidates in Ghana, I find that voters in competitive, non-segregated districts are the most willing to cross party lines. Additional data on actual public goods distribution supports the mechanism. Data from Ghana’s 2020 parliamentary elections confirm the external validity of the findings: party switching is highest in this type of district. My results demonstrate the influence of constituency characteristics on electoral accountability.