Romney turns guns on ascendant Gingrich

Republican presidential candidate Mitt Romney's campaign is aggressively targeting Newt Gingrich - though so far the candidate is leaving the dirty work to his surrogates.

On Thursday, the Romney camp sought to revive Gingrich's controversial characterization of the House GOP's Medicare plan as "right wing social engineering," with Romney Communications Director Gail Gitcho emailing reporters to say Gingrich's "attack on Paul Ryan's plan as 'right-wing social engineering' - and then denying his own attack before doubling down on it - is the kind of Washington politics that Americans are tired of."

"Lifelong Washington insiders can't fix the mess they helped create," added Gitcho.

That theme was also picked up by two Romney backers, former Missouri Sen. Jim Talent and former New Hampshire Gov. John Sununu, who told reporters on a conference call Thursday that Gingrich is "not a reliable or trustworthy leader," as Talent put it.

"For Newt Gingrich, in an effort of self-aggrandizement, to come out and throw a clever phrase that has no other purpose than to make him sound a little smarter than the conservative Republican leadership, to undercut Paul Ryan, is the most self-serving, anti-conservative thing one can imagine happening," said Sununu. "He gave the liberals and the Democrats the ammunition they needed to moot, if you will, at least for the time being, Paul Ryan's presentation."

Talent said that "the president is going to win" if the election is about the Republican nominee, and cast Gingrich as undisciplined enough to allow the Obama campaign to put the focus on his rival.

"If the nominee is Newt Gingrich, then the election is going to be about the Republican nominee which is exactly what the Democrats want," he said.

Talent added of Gingrich as House GOP leader: "You were in a situation where you would get up in the morning, and you would have the to check the newspaper, the clippings, that was before the internet, to see what the speaker had said that day that you were going to have to clean up after in your own district."

New Jersey Gov. Chris Christie, meanwhile, implied that Romney's rivals could embarrass the country with their personal behavior -- a potential shot at the thrice-married Gingrich.

"When you look at candidates, say, 'Is this the kind of person who's always going to make me proud in the Oval Office and never have to worry will embarrass America? That I'll never have to worry will do something that will just make me ashamed?' (Romney) just won't," Christie said.

A political action committee backing Romney is spending $3.1 millionon ads to boost the former Massachusetts governor in Iowa. While the first ad from the group went after President Obama, the group could set its sights on Gingrich in the coming days and weeks.

Thursday's developments signaled a much more aggressive posture from Romney, who has seen Gingrich shoot ahead of him in both national and early state polls. Romney has previously sought to stay above the nomination fray and cultivate an air of inevitability, but Gingrich's sudden rise - he leads Romney by 14 points in Iowa, according to a new CBS News/New York Times poll - has forced Romney to engage his rival.

Gingrich, meanwhile, has vowed not to be an "attack dog" against the other GOP candidates, vowing "a positive, solution-oriented campaign" But he has made a number of implicit digs at Romney.

Among them was a comment last month that seemed designed to reference Romney's reputation for changing his position: "I wouldn't lie to the American people. I wouldn't switch my positions for political reasons...It's wrong to go around to adopt radically different positions based on your need of any one election...people will have to ask themselves, 'What will you tell me next time?'"

The two men will face off in a debate Saturday night in Des Moines that will be closely watched for indications of just how aggressively - and negatively - the two candidates will engage each other.