The Anchoress argues that the Obama candidacy shows that America is now a post-racial society. [here]
I agree with her point. Obama is receiving just about the same amount of support that white Democrats do in presidential contests. I have run the numbers. Since World War Two, in head to head presidential contests in which there was no strong third party challenge, Democrats have averaged about 47 percent of the vote. Republicans have averaged about 51 percent. Democrats have received more than 50 percent of the vote only twice. Republicans have done so seven times. Obama is polling slightly less than 50 percent right now, which is about what Democrats can expect. It is McCain who is running significantly behind his party's average. Obama seems not to have benefited from nor been hurt by his skin color.
That being said, I would go a bit further than the Anchoress. I would hold that Republicans have been a post-racial party for some time -- at least a couple of decades now -- and that the last racist stronghold has been the Democratic Party and its institutional support structure.