This is a good run-down of why Bernie was slaughtered in the Southern primaries and what this means for the future. Basically, if a leftist presidential candidate wants to be successful in the South, that candidate has to have relationships with the black community and be able to speak to their concerns. To say the least, Bernie Sanders did not have those relationships or that ability. Moreover, if Progressives want to win in the South more broadly, they have to put race front and center in their analysis, organize on the local level to elect candidates, and simply ignore or isolate the reality that this might upset white voters who weren’t going to back your ideas anyway (this was the ultimate factor that doomed Operation Dixie in 1946, when the CIO was so fearful of alienating whites that it isolated the black workers who actually wanted unionization and never won the whites over). In the end, the true Democratic Party base is black women. Unfortunately, parts of the white college-educated left think they are the base because they are the most rabid for pushing policies to the left, but what “the base” means is your most hardcore voters that don’t need to be convinced to vote for you but do need to be convinced to work for you, i.e., the idiots who will back Trump even if he personally shoots someone. This is the ticket for southern success. It ain’t easy, but it’s necessary.