We heard a lot about change versus experience in the four-plus days between Iowa and New Hampshire. That's obviously a relevant dichotomy. But a better way to think about the Democratic race is as a batte of second thoughts. That is, the winner will be the candidate who better weathers voters' second thoughts about their voting decision. 

I think it's safe to say that voters' second thoughts about a second Clinton era helped fuel Obama's victory in Iowa. Then, in New Hampshire, second thoughts about whether Obama should be "annointed," as he put it, probably contributed to his defeat. (Or, conversely, second thoughts about whether Hillary should be nudged aside so quickly.)

So who has the advantage in the second-thought primary? At this point, I'd say Obama. That's because, while both candidates have been done-in by second thoughts, the s.t.'s that hurt Clinton had do with her personally, while the s.t.'s that hurt Obama had mostly to do with process. (They were s.t.'s about the way voters make their decision, not the candidate himself), and should therefore subside over time.

Having said that, Obama could still suffer from more personal s.t.'s--whether he has the experience or toughness to be president. But, at least if you buy the conventional wisdom on the race so far, we haven't really seen that particular s.t. surface in voter's minds.

--Noam Scheiber