No Great Migration also likely means no Northern Cities racial backlash among working/middle-class whites.
It may also mean no major civil rights bills, at least in the 1960s, since the growing power of non-disenfranchised Northern blacks was a major part of what pushed Northern politicians to back the civil rights movement.
It also likely means that the Democrats don't embrace Civil Rights either, as blacks are not forming part of the urban coalition in the Northern states either.
I could see the GOP taking a more active role in civil rights legislation, especially voting rights, as it would help the party break into the South.
