If Obama wins Florida by an 8% margin
I'll stop you right there. There's no way in hell Obama wins Florida by 8 points. That means he will have to win nationally by 12 points at least which won't happen.
Would you have said in April 2005 that Barack Obama would've even came close to being the democratic nominee?
If the economy is "fixed" in four years, 12 points is possible.
I'd argue that each party has a baseline of 45%, and its the 10% in the middle that swing the election.
I would further argue that the Republican candidates that are most likely to implode nationally are ones like Huckabee and Palin that entrench the negative image of the GOP as being white, Southern, rural, etc. These types of candidates might not do too badly in the white parts of Texas.