(yes, I know MLK was a Republican)
I for one think that the Democrats may be losing a big piece of the black vote, and they can't see it coming. Gay marriage and immigration doesn't sit well with blacks. They still will win the majority of the black vote, but the Dems are in for a surprise when they see how that majority has shrunk. Also a lot of blacks are planning on sitting out this year, which is the first step to switching parties for good.