This seems right:

The Huck surge makes it harder, not easier, for Rudy to win the nomination. Now that many evangelicals have a horse in this race, it would be very hard to tell them that not only will their guy not get the nomination, but they’ll have to settle for a pro-choicer.

The line that supporting Huckabee empowers Giuliani is, as I have said, one that is very convenient for Romney and his supporters, but it must also be very satisfying for the Giuliani campaign to be perceived as the beneficiary of fighting among candidates on his right.  It lends his campaign undeserved prestige and would have cemented his “national frontrunner” reputation if voter preferences hadn’t started getting in the way.  The ideal Giuliani scenario would have involved a single relatively weak social conservative candidate forcing all other contestants out early on, allowing Giuliani to knock his sole remaining major competitor out of the race and claim victory.  Instead, national and state polling (e.g., South Carolina) show that just the opposite is happening: more social conservative candidates are becoming competitive in more states, and some of them provide a ready alternative to Giuliani on national security.  At the national level, Giuliani was functioning as the default candidate with high name recognition–and his preeminence in national polling was the main source of the media’s anointing of him as the frontrunner.  Now that voters are becoming aware of other options and learning more about Giuliani, they are fleeing the latter, as the original conventional wisdom almost a year ago assumed they would.  The more competitive social conservative candidates there are, the harder Giuliani has to work to peel off evangelicals, who may be sympathetic to his dangerous ideas on foreign policy but who can find equally foolish foreign policy ideas among the pro-life candidates.  Giuliani needed to have Thompson and Huckabee go the Brownback route, which would have made Romney his chief and only real rival.  Because of the unavoidable problems Romney has with a large number of evangelicals, Giuliani could have won that scenario.  Huckabee may be terrible, but he may be preventing Giuliani’s success by returning social issues to the center of the debate.  (Of course, his cluelessness on foreign policy may make his surge very short-lived.)