Understanding the South—Republicans in Alabama and Mississippi reside in a universe where virtually all white voters vote Republican. And no, this isn’t just an Obama thing—Obama only got 11 percent of the white vote in Mississsippi in 2008, but that was barely worse than the 14 percent John Kerry got four years earlier. Increasingly, being a Democrat in the Deep South—a Democrat when it comes to national politics—means being African-American. This means that political polarization in the Deep South is of a different sort than it is elsewhere. @AlecMacGillis