From Matt Yglesias.
...Ultimately, the only thing we really know about either candidate's base of support is that Obama's is slightly larger, and that he's demonstrated more ability to expand it over time through campaigning. Either way, though, I think Democrats can be fairly confident. What voters "know" about the three candidates right now is that John McCain is a war hero maverick, Hillary Clinton is a castrating harpy, and Barack Obama is a radical black Muslim and given that . . . the race is about tied. As Ross Douthat points out that's not good news for McCain.