Sarah Palin might not normally be a viable candidate, but you're talking about a presidential election season where a LOT of Democrats are disaffected, a lot of Republicans are likely to show up at the polls just to try to get the White House back, and a fair number of independents would rather vote for a third party than vote for Obama or an anti-choice Republican candidate. That raises her chances of being elected a fair amount, if she wins her party's nomination.

There are some people who are saying Clinton will run in 2012. I don't see that happening. She plays too closely to the party rules (and probably loves her political career far too much, as that would be political suicide) to do something like that. The only way that would happen would be if Obama refused to run or was pressured not to run, and I don't see that happening, either.