Last Minute Polling Crack

Nate Silver:

McCain's chances, in essence, boil down to the polling being significantly wrong, for such reasons as a Bradley Effect or "Shy Tory" Effect, or extreme complacency among Democratic voters. Our model recognizes that the actual margins of error in polling are much larger than the purported ones, and that when polls are wrong, they are often wrong in the same direction.

However, even if these phenomenon are manifest to some extent, it is unlikely that they are worth a full 6-7 points for McCain. Moreover, there are at least as many reasons to think that the polls are understating Obama's support, because of such factors as the cellphone problem, his superior groundgame operation, and the substantial lead that he has built up among early voters.

McCain's chances of victory are estimated at 1.9 percent, their lowest total of the year.