This one shows how Obama and Clinton did in the primaries. The redder the county, the better Clinton did; the bluer the county, the better Obama did. (Ignore Michigan and Florida; they didn't have real primaries.) You can see Clinton had an obvious region of strength from her home state of NY, down the spine of the Appalachians and through the Ozark states. This region is also known as the Upland South, or Appalachia.
And this one shows the voting shifts from 2004 to 2008. Bluer areas shifted towards the Democrats; redder areas shifted towrds the Republicans.
Notice anything about these two maps? There sure seems to be a strong correlation between the red areas in both of them, huh? In other words, it sure looks like Obama was unpopular in Appalachia. Indeed, that was a common theme in political commentary, during the primaries and right through the aftermath of the general election.
This analysis was wrong, though. It's true Obama underperformed in Appalachia. But another way to characterize Appalachia is as the area of the South which has few blacks. Now consider this map:
It shows the percentage of blacks in every county. And as you can see, they're concentrated in much of the south - much of the south outside Appalachia, that is. Of course, Obama did really well among blacks, boosting both the Democratic percentage of their vote and raising turnout among that demographic. So he actually did comparatively well in parts of the south with large black populations. In the remainder of the south - not so much.
But what the conventional wisdom sometimes missed was that Obama did just as poorly among southern whites in areas with lots of blacks, if not more so. A final map, from dreaminonempty, to drive the point home:
Obama's worst states among whites were Louisiana, Mississippi, Alabama, and Georgia (all of which, along with South Carolina, went for Goldwater in 1964, incidentally: the only states besides Goldwater's home state of Arizona to do so). He did slightly better in those states overall, though, thanks to his huge margins among blacks. So Obama didn't have an "Appalachia problem," as some have alleged. He had a southern whites problem. (Though the better way to say it, probably, is that Southern whites had an Obama problem.)
Of course, not every region in the south was so hostile. He actually won Virginia and North Carolina, for instance. These are all areas where the New South has taken hold - areas which are more urbane, cosmopolitan, wealthier and more educated. He didn't win whites in these states, but he did do better among them than he did in the more rural and economically stagnant areas of the south.
It's fair to say that race has something to do with this pattern. But obviously, despite this obstacle (which was limited mostly just to the South), Obama won anyway. And this is progress. What will be interesting to see is what the results will be in 2012. Obama may or may not win, but here's a bet: those areas of the south will not diverge from the rest of the country as much as they did in 2008. They're among the most conservative parts of the US, of course, and I don't expect that to change. But I don't think they'll be quite so divergent. I think four years of an African American president will have an effect in these areas; I think whites will get used to the idea. And in so doing, the country may actually be able to make even more racial progress than was made in electing the first black president in the first place.