Peter noted this poll, which has Huckabee outpacing the field in Georgia, and Obama barely ahead of Clinton. I can’t find it on the web, but the print edition noted a huge disparity between black and white support for the two Democratic candidates. As Peter S. noted, racial fault lines in the Democratic coalition are potentially very big. If HRC wins, can she count on enthusiastic African-American support in the fall?
On the other hand, the willingness of both candidates’ supporters to take umbrage at real or perceived slights is, I think, a problem. Presidents need to have a thick skin; sensitivity of this sort is "unpresidential" and will not wear well. If I were Barack Obama or Hillary Clinton, I’d very vocally and visibly shrug all of it off.