Poor Mitt Romney. He's a serious guy, with an impressive grasp of complicated issues. He wants to be president, presumably, to accomplish big things. And now he's reduced to trying to fend off Mike Huckabee in Iowa with an ad highlighting a trivial pseudo-difference on a tiny aspect of their respective gubernatorial records, on the question of what benefits states should provide or deny to the kids of illegal immigrants. The ad (every word of which is obviously and clunkily a product of polling and focus-grouping) may hurt Huckabee - though I'm doubtful Christian conservatives will necessarily rally to a guy who's so proud he denied kids of illegal immigrants who attended public high schools in the state the opportunity to go to state colleges. But it sure makes Romney look small. Meanwhile, Giuliani's shrinking, and Huckabee hasn't exactly articulated a national vision. This gives John McCain and Fred Thompson a big opportunity. In tomorrow's debate, they can go presidential. They can draw a contrast with the squabbling governors and mayor next to them on stage. It is, after all, a wartime election, even if voters occasionally forget it. There are, after all, big domestic issues at stake, like entitlement reform and the courts. Thompson and McCain are lagging in the polls, but they are (now more than ever, ironically) the most presidential candidates in the race. Can one of them pull off an upset by refusing to pander and to squabble, by refusing to stoop to (try to) conquer?