The Tightening?

Nate Silver parses the day's polls:

What we may have witnessed is some sort of dead cat bounce for John McCain. One possibility is that, as more voters are taking advantage of early voting windows across the country, the pollsters are finding that some voters whom they considered "unlikely" voters have in fact turned out to vote. Zogby gives Obama a 21-point lead nationwide among people who have already voted, and SurveyUSA and Civitas peg his advantage among early voters in North Carolina at around 20 and 30 points, respectively.

Jesus.