Let me play armchair strategist for a minute for each campaign.
Huckabee has done a terrific job of rallying evangelical voters by emphasizing that he is one of them. The challenge for him right now, it seems to me, is to show that he can move beyond that base. He has distinctive positions on enough issues that he could have a wider appeal, but he would have to alter the way he is selling his candidacy. The question is whether he can do that without losing some of the voters he has gained and is gaining right now. But if he does not find a way to do it, he won’t get the nomination.
Romney is hitting Huckabee over the tuition-discounts-for-illegal-immigrants question. That strikes me as being pretty far away from the center of immigration policy: If Huckabee’s official position on immigration were to take effect–leaving aside the question Krikorian and Kaus raise about whether Huckabee really believes his official position–tuition discounts wouldn’t matter much because there would be fewer illegal-immigrant teenagers to give them to. But I wonder if it wouldn’t make more sense for Romney to try to do to Huckabee what was done to Howard Dean in 2004: make him seem unelectable, even to people who share his views. (Note that in 2004, what seemed to sway voters was Dean’s unelectability rather than the eventual winner’s electability.) Hitting Huckabee from the right runs counter to that strategy.
Of course, if Huckabee takes my advice for him then Romney won’t be able to use this tactic quite as effectively.