Mccain's stunning collapse in polls after Lehman Brother's bankruptcy.

[Adam Griffin]

In past elections (including 2008), RV screens remained the primary polling method until just a few weeks before the election. While McCain made a fool of himself during the collapse by suspending his campaign (and picking Palin), it was generally perceived that 2008 was going to be a very good year for Democrats long before the official collapse. I don't think there were many objective people even during the summer who thought McCain was going to be the next president.

Around the middle of September, the polls went from being mostly RV to mostly LV. Given that Obama won like 70% of first-time voters in 2008, it's not particularly surprising that the polls shifted so dramatically once they really started taking into account who was definitely voting rather than who was simply registered.