The pundits are trying to figure out if or when John Edwards will drop out of the Democratic race and which candidate would benefit if he did so. Given his apparent leanings toward Obama, one reason for Edwards to stay in, as the New York Times notes today, is that he splits the white vote with Hillary:

some political strategists say Mr. Edwards also has another compelling reason to stay in, at least in South Carolina. He could end up sharing the white vote with Mrs. Clinton, thus helping Mr. Obama, whom Mr. Edwards has signaled he favors.

As Phil Klinkner points out at Polysigh, Obama’s white support has been disturbingly low and consistent, suggesting a possible ceiling in the support he draws from whites:

The exit polls from Nevada provide more evidence that Obama has been unable to break out of his ceiling of approximately one-third of the white vote. In fact, in each of the three Democratic contests thus far, Obama’s support among whites has been remarkably consistent:

Iowa: 35%
New Hampshire: 36%
Nevada: 34%

If this 35% ceiling does, in fact, exist, it’s interesting to compare it to Jesse Jackson’s performance in 1988. Despite the passage of 20 years and the fact that Jackson and Obama are very different candidates and personalities, Obama hasn’t performed significantly better than Jackson. During the 1988 primaries, especially once the race narrowed down to Dukakis and Jackson, Jackson’s white support ranged between 20 and 35 percent.

I want to believe that a ceiling doesn’t exist or at least that it isn’t that low. We’ve come a long way as a country since 1988, and Obama is a very different candidate than Jackson was. But those exit poll numbers make me nervous…