I'm betting on Carter in 1980.
It could be. The man doesn't know how to govern and it looks like his administration is in a mess right now.
Clinton got that rap early, and it is questionable that he ever learned to govern. He won decisively in 1996 -- most likely because he was lucky. That's not to say that he was by any means a great President. He well played the center.
The current conservative base of the GOP is absolutely not enough to win in 2012. The base must expand to win, and must convince people not in the base that the GOP has better ideas. A repackaging of the George W. Bush agenda ensures an Obama landslide.