Score one for Romney

John McCain and Mitt Romney crossed paths Wednesday night after the two candidates battled back and forth at the Republican debate in California. (GABRIEL BOUYS/AFP/Getty Images)

AFTER JOHN McCain's win in Florida on Tuesday, the Arizona senator finally has a genuine measure of that most precious political commodity: momentum. With only a few days left before the Feb. 5 mega-contest, when more than 20 states will hold primaries or caucuses, that's priceless.

The Sunshine State didn't just elevate McCain, it knocked Rudy Giuliani out of the race (and into McCain's corner). That should give McCain a special opportunity in states that once looked like Giuliani territory.

All that has put the pressure squarely on Mitt Romney to reverse a strengthening campaign tide.

On Wednesday night, when the four remaining Republican candidates squared off at the presidential library of the party's patron saint, Romney rose to the occasion, making some definite progress.

The Romney camp had three principal goals going into the debate: to frame this contest as a two-man race; to put some dents in McCain's reputation as a straight talker; and to portray the senator as out of sync with conservative values.

For many Republicans, this is already seen as largely a two-man race. Although he has committed supporters, Ron Paul isn't much of a factor. But Mike Huckabee, despite his diminished prospects, still could be, at least regionally. He is now concentrating on a handful of Southern states; even if Huckabee fades, it's not clear that Romney would consolidate the conservative vote there. But though Huckabee refused to be left completely out of the limelight, most of the action at the debate was between Romney and McCain.

Here's where Romney fared particularly well: In the long exchange over whether he had called for some sort of timetable for the withdrawal of US troops from Iraq, a charge McCain leveled during the Florida campaign, where he portrayed Romney as wanting "to set a date for withdrawal, similar to what the Democrats are seeking . . ."

As the two argued over the issue, Romney made a strong case that McCain had misrepresented his April 3, 2007, comments on "Good Morning America." Asked then if there should be a timetable for withdrawing US troops, Romney said that President Bush and Iraq's prime minister, Nouri al-Maliki, should privately discuss "a series of timetables and milestones." But Romney also spoke specifically against a public timetable and said he would veto any attempt by Congress to set one. (Several news organizations have fact-checked that statement and come down on Romney's side).

McCain didn't back off, but his attempt to support his contention seemed clumsy and contrived. When Romney said that making the dubious charge amounted to "Washington-style old politics, which is to lay a charge out there, regardless of whether it's true or not," McCain retorted that Romney had gone after both him and Huckabee with "attack ads" and thereby set the tone.

There's truth to that. Still, the long back-and-forth made McCain look small on a night when he would have done better to seem large and presidential. Score that for Romney.

Then there's the matter of attempting to depict McCain as outside the conservative mainstream.

Romney tried hard, arguing that McCain had run afoul of conservative thinking by voting against the Bush tax cuts, pushing restrictions on advertising in McCain-Feingold, cosponsoring last year's (failed) immigration plan, supporting a federal cap-and-trade system to reduce greenhouse gas emissions, and opposing drilling in the Arctic refuge.

McCain's reply was less to rebut than to launch a tough critique of Romney's own record as governor of Massachusetts - an assessment that left Romney scrambling to defend his days as Bay State CEO.

Now, Romney's attempt to discredit McCain with conservatives is made difficult by his own opportunistic political repositioning. At the debate's end, after Romney had made his case for why Ronald Reagan would endorse him, McCain noted, cuttingly, that "Ronald Reagan would not approve of someone who changes their positions depending on what the year is."

Nevertheless, some of the stands Romney highlighted are the sorts of things that, while endearing McCain to moderates, make conservatives see red. And as a debating matter, Romney presented his case crisply and clearly.

In the end, he had the best night. There was no Reagan moment at the Reagan Library, which is to say, his was a win on points, not a knockout. And it was blunted some by the news that Governor Arnold Schwarzenegger of California would endorse McCain.

Still, his performance could give Romney something to build on as the Super Tuesday campaign enters its final hectic days.

Scot Lehigh's e-mail address is lehigh@globe.com.