Blumenthal takes the temperature of the race in Massachusetts:
If you accept the very close margins on the PPP and Rasmussen surveys as real, then Brown is successfully persuading a lot of non-Republicans to support him who typically vote Democratic.
Here’s a hypothesis that might explain the pattern: if Brown ekes out a victory or comes within a few percentage points of winning, it will because he wins the support of a lot of voters — most of them independent — who typically vote Democratic. Brown has probably not yet closed the sale with these voters, given their prior vote history, but they are poised to support him. Perhaps it is harder for them to tell a live interviewer they are ready to vote Republican. Perhaps the more anonymous nature of the automated methodology better simulates the act of voting which will ultimately force a decision.
Or perhaps Martha Coakley is a machine hack who doesn’t deserve elevation. And Massachusetts voters are ready for another well-timed swipe at the one-party state that too often takes them for granted.