It's surprising that no counties in the deep South switched to Romney, and instead Obama actually gained some. Looks the Black population is slowly rising in its proportion of the population, and we might see many more blue counties in states like Mississippi and Alabama a few decades from now.
The Republicans have probably maxed out the number of counties they can win in the south. It's quite polarized down there by racial lines. It's not so much the black population growing but that black turnout ticked up a little in MS/LA and white turnout dipped slightly
