Romney took the fight to an unexpectedly-back-on-his-heels Newt Gingrich last night, lashing him for an immigration-related radio ad which the Gingrich campaign had had to modify after Florida GOP Sen. Marco Rubio criticized it. The ad had called Romney “anti-immigrant,” a charge which the Miitt-bot, with realistic looking outrage, called “simply inexcusable.” Then Romney stopped Gingrich’s attacks about his investments cold by pointing out that Gingrich himself has investments in Freddie Mac and Fannie Mae (“Have you checked your own investments?”)

As MSNBC’s “First Thoughts” declares this morning, “Romney owned Gingrich.” They add: “If  Mitt Romney wins the nomination, we’ll look back and say the first hour of last night’s debate and say that was when he finally put it away.”

Here’s why the debate was a critical fumble for Gingrich: His biggest selling point has been the idea that he alone could “go toe-to-toe” with Barack Obama in a debate. Now he faces the transitive property of politics: If Romney can own Gingrich, then Romney must also have the capacity to face down the president. If Newt’s no longer the only one who can face down the dread Obama, what is the raison d’etre of his candidacy? To colonize the Moon?

[See editorial cartoons about Gingrich.]

(And let’s take a quick moment to marvel, once again, at conservatives’ schizophrenic view of Obama: They simultaneously believe him to be bumbling amateur incapable of public utterance without a Teleprompter … but also so uncommonly skilled that he will be hard near impossible to match in a debate; conservatives view him as a terminally ineffective president incapable of accomplishing anything … but also a malevolent force single-handedly transforming the nation into a Eurosocialist Hell on Earth. They’ve elevated cognitive dissonance to a new and mind-boggling level.)

This is not to say that Romney had a perfect debate. Former Pennsylvania Sen. Rick Santorum, as the MSNBC gang, notes “at least rented Romney.” Santorum repeatedly scored Romney on his Massachusetts healthcare law, though when Romney told him that the issue wasn’t “worth getting angry about,” he missed the opportunity for a Goldwater-ian moment: The erosion of liberty is absolutely something to get angry about, governor.

Romney also did himself no favors with his blind trust response to questions about his wealth. But the debate capped a good week for Romney. Polls are trending in his favor and the GOP electoral , with a strong push from the establishment (which now seems to include the Drudge Report), has had a stinging case of morning after regret after their Palmetto State dalliance with Gingrich—aided by Gingrich’s self-described grandiose vision of a 51st state on the Moon. Maybe President Romney can put him in charge of NASA.