Demographics & Population
This pushback about undocumented immigration which tends to dominate political debates put to the backburner a more rational discussion about immigration policy. We are going to have to have a reasonable flow of immigration to the US to keep our labour force robust.
Chicago was the big magnet (for blacks) for many, many decades, moving out of the South in the first part of the 20th century... But in the last 25 years, blacks have been leaving the North, as jobs are not as plentiful as they once were, and the South is more palatable to blacks because of civil rights changes.