Three footnotes that weren't quite worth a post unto themselves:
1. Around 337,000 North Carolinians have already voted in their state's primary, a fraction that is likely to represent approximately one-quarter of the eventual turnout. According to some data mining done by the Center for Congressional and Presidential Studies, around 38 percent of those voters have been black. As you'll find from playing around with our prediction tool it is very hard for Obama to lose the state if black turnout winds up at 38 percent. Even if he "only" won the black vote 85-15, and lost the white vote 70-30 -- he would still win the state by 2 points if black turnout was 38 percent. If we instead use the numbers from Survey USA's most recent poll: Obama loses whites 61-30, but wins blacks 87-11 -- he would win the state by 10 points given those turnout demographics. EDIT -- the percentage of black voters is apparently 39.3% based on the very latest numbers.
2. North Carolina uses a modified primary, rather than an open primary. What that means is that while independents may vote in the Democratic primary, Republicans cannot. Also, it is not possible to change one's party affiliation at the last minute -- the state must receive any changes by the registration deadline, 35 days ahead of the election. Moreover, there is a highly competitive Republican primary in the state's gubernatorial race. Long story short: while independent voters are something of a factor in North Carolina -- they make up about 16% of the early voting turnout -- Republican voters really aren't. An Operation Chaos voter would have had to change his registration weeks ahead of time -- and sacrificed the chance to vote in the gubernatorial race.
3. While those first two items probably bear well for Obama, here's something that I think might be worth a point or so for Clinton. A couple of pollsters, like Zogby and SurveyUSA, have been picking up a fairly large "other" vote in their North Carolina surveys, particularly among white voters. I would guess that some of these people are folks that intend to vote for John Edwards. However, I would surmise that those people who were still planning to vote for Edwards at this stage would tend to be low-information voters that will probably default to Clinton.