The Great Migration reached its peak in the years between 1940 and 1970, when decadal outmigration rates from the US South among Blacks surpassed 10%. During the same period, the long-standing struggle of African Americans to end racial discrimination was consolidated into a massive social movement. The civil rights movement grew in intensity during the 1950s and 60s, culminating in the enactment of the Civil and Voting Rights Acts of 1964-1965. It is hard to imagine that the temporal correlation between these social and political developments and a demographic shift of the size of the Great Migration would be purely coincidental.
Disenfranchisement was one of the reasons why Southern Blacks decided to migrate in the first place. Literacy tests, grandfather clauses and poll taxes had been employed throughout the South as means to lower Blacks’ ability to influence political outcomes (and see Trevon Logan’s post for the use of political intimidation and violence to silence the expression of Blacks’ political preferences). Such legal restrictions to voting were largely absent in the North. Black migrants were quick to take advantage of this by registering and turning out to vote at rates comparable to, and sometimes higher than those of the rest of the population.
Shifting voters across space and extending the franchise to a large swath of the population can dramatically alter the political equilibrium. The political effects of the demographic change induced by the Great Migration would have been felt both in the North and in the South, impacting local politics, as well as national level elections. Aside from voting patterns, the Great Migration had the capacity to fundamentally change social dynamics and trigger mass mobilization among Blacks. As the size of the Black population grew in Northern areas, so did the Black movement’s organizational capacity. Northern urban centers were fertile soil for the creation of new institutions to advance the interests of the Black community. Migrant networks also increased the connections between North and South, bringing Southern issues like racial violence and Jim Crow to the attention of a broader public, both black and white.
In a recent working paper co-authored with Alvaro Calderón and Marco Tabellini we undertake a quantitative investigation of some of the causal links between the Great Migration and Black political empowerment. Our focus is on the local effects of the Great Migration in Northern and Western counties and congressional districts. I refer the interested reader to the paper for details on our identification strategy, and will only mention some of the results here. Between 1940 and 1970, counties with large inflows of Southern Blacks saw a surge in support for the Democratic party. During this period, the Democrats were emerging as the party of Black interests, a process that started in the Northern states before it was completed at the national level. As we verify in our data, and for the entire period between 1943 and 1965, Northern Democratic congressmen were more likely than Northern Republicans to support bills on civil rights, a pattern that was reversed among Southern legislators. The observed increase in the Democratic vote share caused by the inflow of Black migrants can therefore be interpreted as increased support, as well as increased demand of the electorate for a civil rights agenda.
Black migration also increased grassroots activity in support of civil rights. We show this with data from the project Mapping American Social Movements, directed by James Gregory in the University of Washington. Black inflows led to an increase in the number of protests organized by the Congress of Racial Equality, and to the founding of more local chapters of the NAACP.
Increased demand for civil rights, as measured by voting patterns and local activism, is mirrored in changes in the behavior of Northern legislators. To account for changes in the boundaries of congressional districts over time, we construct a time-invariant mapping by collapsing districts back to a base geography (for more on spatial merges see Adam Slez’s series of posts). We then examine changes in the behavior of the “average legislator” in those collapsed units. Legislators’ voting records on civil rights bills become more liberal in districts that receive more Black migrants. Using data on discharge petitions, collected by Kathryn Pearson and Eric Schickler, we also find that Black migration increased the likelihood of more direct congressional action to promote civil rights.
Naturally, much of the growing support for civil rights in Northern counties came directly from Black migrants. An important question then is how Black inflows influenced white Northern voters. Theoretically, the effect could go in either direction. The economic history literature has emphasized backlash to Black in-migration and patterns of “white flight”. Such reactions may have manifested in regressive racial attitudes that in turn influenced whites’ voting patterns. Yet the link between whites’ reactions to racial mixing at the neighborhood level, and their attitudes towards civil rights – until the mid-1960s largely an issue centered around Jim Crow and the South – is not that clear. Black in-migration may have depressed housing values, but it also transmitted information and raised the salience of Southern injustices. In The American Dilemma, Gunnar Myrdal identified this channel as central for Black empowerment. “A great many Northerners, perhaps the majority, get shocked and shaken in their conscience when they learn the facts. The average Northerner does not understand the reality and the effects of such discriminations.”
Inferring white voting patterns from aggregate voting shares is a formidable problem of ecological inference. The magnitude of our estimates suggests that, under reasonable assumptions on Blacks’ turnout rates and vote choices, white voters also contributed to the rise of the Democratic vote share in the North. Some of our other data sources speak even more clearly. Protests with white participants increased where Black migration was larger. And individual level data from the early American National Election Studies and Gallup Opinion polls, which record the race of the respondent, show that whites’ support for civil rights, desegregation, and the Democratic party was higher in areas with more Black migrants.
It is hard to precisely identify the mechanism behind these reactions. Was Myrdal right, and Black migrants diffused information that sensitized the white population to issues of civil rights? The effects of the Great Migration that we estimate come largely from counties with lower historical prevalence of discrimination, as proxied by, for instance, past instances of racial violence and presence of miscegenation laws. This finding is consistent with an information mechanism insofar as more progressive counties would be more sensitive to news of injustice and racial violence.
The heterogeneity we observe is also consistent with political motives behind support for civil rights. The Great Migration was more impactful in counties with a stronger presence of manufacturing and unskilled workers and higher unionization rates in the CIO. Thomas Sugrue’s work, as well as Eric Schickler’s in-depth analysis of the New Deal coalition, highlight the central role of organized labor and progressive forces in the Democratic party in the fight against racial discrimination. Such forces made civil rights part of a broader progressive agenda, which in turn was effective in incorporating Black voters in the Democratic front.
This is not to say that all Northern whites necessarily welcomed Black migrants. In fact, our data confirms the findings of prior work on white flight in Northern epicenters of Black migration. Yet our results are not explained by selective population sorting. This then implies that support for civil rights increased among whites, simultaneously with residential segregation. In fact, the effects we estimate are higher in counties that were already more segregated by 1940. While we cannot say for sure, it is possible that liberal whites in segregated counties were able to align themselves with struggles for justice and equality, while at the same time avoiding interactions with Black migrants in residential markets and school districts – the primary points of friction in Black-white relations at the time.
Our study is only able to identify effects on local dynamics caused by Black migration. We do not explore whether the migration led to more fundamental developments at the national level, or whether the patterns we observe in the North were cancelled out by equivalent, but opposite in direction, changes in the South. Keneshia Grant provides compelling evidence that Black voters swayed the balance of power in important local and national elections, contributing to the shift in the Democratic party’s platform. As pointed out by Bill Collins, the multidimensional channels through which the Great Migration influenced political change deserve more scrutiny by the HPE literature. While one would not go as far as claiming that we would not have civil rights without the Great Migration, mounting evidence suggests that major political and social developments in the history of the United States would have been quite different without it.
 Moon, H. L. (1948). Balance of Power: The Negro Vote. Wilson, J. Q. (1960). Negro Politics: The Search for Leadership.