John McIntyre over at Real Clear Politics makes a smart point about Romney, Huckabee, and Iowa: 

For the Romney campaign the silver lining in Huckabee's move into the first tier--and it is not an unimportant silver lining--is that Huckabee has totally shaken up the expectations for Iowa on the GOP side. Because of this resetting of expectations in December, if Romney is able to hold off Huckabee in Iowa it will be a huge win for his campaign. A win that would allow the Romney campaign to get the kind of momentum they were looking for when they originally laid out their sling-shot strategy to the nomination. (Win Iowa, win New Hampshire, win Michigan, make it a two-person race against Giuliani, combine the early wins with Romney's personal wealth to overwhelm Rudy).

I'm not sure I would go far as to say it would be a huge win, but I do agree that Huckabee has scrambled expectations in Iowa--and will continue to do so over the next five weeks--and that Romney will be able to say "a win is a win" if he pulls it out. I also agree that, under that scenario, he'll have all the momentum he needs heading into New Hampshire. (Though, again, I wouldn't quite consider it a tidal wave of momentum.) It would have been much, much worse for Romney if the plot of Huckabee's progression over time were shifted about a month to the right.

In general, I'm not quite as bullish as John is on Huckabee in Iowa (or anywhere). I think Huckabee probably has a ceiling there of between 25 and 33 percent--there are only so many people who will vote for a guy who's still highly unlikely to win the nomination--though he has a very high floor, too, given the intensity of his support. I think between Romney's money and organization, his greater plausibility as a nominee, and the scrutiny Huckabee will be receiving on immigration and taxes, he's still somewhat more likely to win the caucuses.

--Noam Scheiber