Abstract This article shows how the migration of millions of Southern whites in the twentieth century shaped the cultural and political landscape across the United States. Racially and religiously conservative, Southern white migrants created new electoral possibilities for a broad-based coalition with economic conservatives. With their considerable geographic scope, these migrants hastened partisan realignment and helped catalyze and bolster a New Right movement with national influence over the long run. More than just augmenting the conservative voter base outside the South, they influenced non-Southerners by building evangelical churches, diffusing right-wing media, and mixing through intermarriage and residential integration. Tracking non-Southern households, we show that exposure to Southern white neighbors increased adoption of conservative religious norms. Overall, our findings suggest that this mass migration blurred the North–South cultural divide and reshaped the geography of conservatism in the United States.

Abstract This paper develops a new framework for understanding when and how migrants shape culture, applying it to the Confederate diaspora—a small migrant group that left a large cultural imprint. Southern Whites that migrated after the Civil War played a pivotal role in spreading Confederate symbols and racial norms across the U.S. by the early 20th century. Their far-reaching influence stemmed from two key conditions: (i) an ideological intensity rooted in their experiences of slavery, secession, and military defeat and (ii) access to malleable power structures during westward expansion and post-war reconciliation. These conditions enabled them to transmit Confederate culture to both kin and non-Southern neighbours and to expand their reach by mobilising civil society organisation and leveraging positions of authority. They shaped policies and institutions that helped entrench racial norms and inequalities in labour markets, housing, and the criminal justice system. Our findings provide empirical foundations for understanding how migrants can transform local culture, rather than merely assimilate.