Abstract
<p>We further explain the puzzle of steadfast Black Democratic partisanship by providing new theory and evidence on the role of racial segregation. Using large surveys and an instrumental variables approach, we demonstrate racial segregation reduces Black Republican partisanship. These effects are driven by racial segregation preventing Black ideological conservatives from identifying with the Republican party instead ofthe Democratic party. We push the literature forward by showing this relationship is net of partisan segregation and alternative mechanisms that could strengthen Black Democratic partisanship such as limited political knowledge and group consciousness, underscoring the role of social constraint. Our theory and evidence further establishes that the roots of Black Democratic partisanship are geographic in origin.</p>