Most of the surveys out of South Carolina show Obama with about a 10 point lead (though there are significant discrepancies...see Mark Blumenthal's post about this). Of course, these polls are somewhat similar to those we saw heading into New Hampshire and Hillary Clinton's unexpected victory there helped her campaign quickly recover from the loss in Iowa.
The loss in New Hampshire was worse for Obama because the polls had him ahead a few days before and, as a result, the media fully expected him to win. Well, South Carolina seems to be setting up in a similar way. Take this excerpt from the Washington Post this morning:
"Late polls showed Obama (Ill.) leading Clinton (N.Y.) and former senator John Edwards (N.C.), and veterans of Democratic campaigns in the state reported that Obama has the superior organization. A defeat here would represent a major setback for Obama heading into Feb. 5, when more than half of the pledged delegates to the national convention are at stake in tests in 22 states."
You can read similar statements from other media outlets and the bottom line is the same: if the polls are off in South Carolina, like they were in New Hampshire, this could be a difficult loss for Obama because he will have failed to meet the media's expectations for a second time. On the other hand, because he is expected to win, how much credit does Obama get if the polls are right? How big a victory does he have to score to exceed expectations? Remember, there are a fair number of delegates at stake in South Carolina, but what's more important is what the story line is going to be between tomorrow and February 5th.