The South Carolina polling continues to show a substantial lead for Obama, while Edwards' rise hints that he could challenge Clinton for second place.
At the moment, Clinton continues to hold a six-point advantage over Edwards, but Edwards has been rising while Clinton has been moving down. Obama, meanwhile, has been fairly steady at around 40-44% support, though with some hint of a small decline in the sensitive estimator. Note however that the Clemson University poll included here had an amazing undecided rate of 36%. That makes every candidate in their poll look lower than in all other polls that have a much lower rate of undecided. The level of undecided is quite sensitive to how the poll is conducted, including whether respondents are pushed as to whether they "lean" towards a candidate. The Clemson poll apparently didn't push at all among undecided voters. We'd be making a mistake to read their data as indicating a decline of support for anyone.
A second place for Edwards would, of course, be good news for his campaign, while Clinton would no doubt argue she had conceded the state to account for a third place finish. But Edwards still has some ground to make up, and late deciding voters remain an unknown-- if they are unhappy with either Clinton or Obama, Edwards can benefit simply by not being one of them. This may be especially true among independents who vote in the Democratic race, and the expected handful of Republicans who show up. (Republicans and independents can vote in the Democratic primary only if they did NOT vote in last week's Republican primary.)
I think the more compelling story of South Carolina will be the exit poll results. Obama has appealed to white voters in previous primaries and caucuses. The pre-election polls have found him getting as low as 10% of the white vote in South Carolina. The potential for racial polarization in this Southern state could damage his ability to transcend race as a basis of voting. Paradoxically, there has been speculation that Clinton can win the votes of black women, a result that could reduce polarization in the exit poll. We'll know much more about how voters decided by Saturday night.
Cross posted at Political Arithmetik.