I'll just reiterate the following post I made over a year ago:

Subject: RE: BS: 2012 Presidential Election
From:Bee-dubya-ell - PM
Date: 17 Mar 11 - 08:55 AM

The deciding factor in the 2012 election will be how many of the people who voted for Obama in 2008 don't vote at all in 2012. Who the Republicans nominate is irrelevant. He'll receive about the same number of votes as John MCain did in 2008. But if Obama's 2008 supporters stay home in large enough droves, that'll be enough.