What if there were a black filibuster in the South during the 60s, or perhaps 70s? That is to say, more radical groups and elements who would grow tired of white bigotry to the point of wanting their state wish to establish a homeland for themselves in one of the states of the American south, and travel to one en masse and promote migration there to any like minded individuals. Such an idea does hearken back to previous black ideas of how to deal with the issue of racism and segregation in American society.
I know this may sound unlikely, but I think it's an interesting concept not out of the bounds of a possibility.
EDIT: To specify, I do not mean that this scenario which is likely, but I do not believe it to be on par with space men abducting the president.