Racial Diversity and Racial Policy Preferences: The Great Migration and Civil Rights.

This article examines the causal relationship between the Second Great Migration (1940–1970), during which over 4 million African Americans moved from the US South to northern and western states, and the rise of support for civil rights outside the South. Using a shift-share instrumental variable approach, the study finds that Black in-migration significantly increased the Democratic vote share in Congressional elections, encouraged the election of legislators more supportive of civil rights legislation, and fostered the growth of Black civil rights organizations such as the NAACP and the Congress of Racial Equality (CORE). Importantly, the research shows that increased support for civil rights extended beyond Black voters to include segments of the white electorate, facilitated by greater awareness of racial oppression in the South and cross-race political alliances, particularly involving organized labor. The findings highlight that the Great Migration reshaped northern political and social dynamics by both changing the electorate's composition and influencing white attitudes toward racial equality, with effects persisting into the contemporary period.