Some people like to make the Dems go populist and the GOP liberal [by now a tired, tired AH cliche that, although is possible, is way too overdone]. Personally, I think the New Left's opposition to Vietnam might be more popular in the Dem camp if it was seen as a "Republican war". Nixon was already gaining with the South in 1960, so you might have that region be somewhat competitive for a while, and if the Democrats go left-libertarian or something, they'll go Republican. Of course, Civil Rights is a pretty big issue for the A-A community, so they might go Republican if they see Nixon as the President who brought Civil Rights, and thus Dems keep the white South and thus the conservative Southerners who would be strongly opposed to the New Left. Basically it all depends on 1961-1968.