(The Blaze/AP) Republican presidential candidate Mitt Romney argued Wednesday that if rival Newt Gingrich can't handle the criticism generated by negative campaign ads, the former House speaker will wilt going up against President Barack Obama. Gingrich, in turn, asked supporters to sign a petition urging GOP candidates to run positive campaigns, free of attack ads, as he has pledged to do.
It was the latest bit of maneuvering in an increasingly heated standoff between the two over hard-hitting campaign tactics.
Romney said Wednesday that there are limits to what he can say to an independent organization that supports his candidacy and is paying to air anti-Gingrich ads on his behalf.
"I'm sure I could go out and say, `Please, don't do anything negative.' But this is politics," Romney said on Fox News Channel. "And if you can't stand the heat in this little kitchen, wait until the Obama's Hell's Kitchen turns up the heat."
Gingrich is collecting signatures from like-minded people who don't want to see the Republican candidates ripping into each other.
"Attacking fellow Republicans only helps one person: Barack Obama," the petition states.
Gingrich has said the attacks by the pro-Romney group Restore Our Future are false. They have poked at Gingrich's past support for climate-change legislation and his work for Freddie Mac, the quasi-governmental mortgage agency.
He declined to say during a news conference in Des Moines on Wednesday what specifically is inaccurate about the ads, citing instead independent reviews that have questioned their validity.
The group's latest ad in Iowa pokes anew at Gingrich's "baggage," including ethics violations that led him to step down as speaker. The group has run $1.4 million in TV ads in Iowa this month and plans to spend another $1.4 million before the Jan. 3 caucuses.
"It would be nice if Gov. Romney was either honest about his former staff and his supporters running negative ads, and either disown them - ask that they take them off the air - or admit this is his campaign," said Gingrich, whom activists have credited for taking a positive tone in his campaign.
Gingrich is trying to end his slide in Iowa, where the attacks have taken hold in the past two weeks, with a show of force from establishment Republican leaders in early voting states endorsing his candidacy.
Iowa House Speaker Kraig Paulsen and New Hampshire House Speaker Bill O'Brien endorsing Gingrich at the Iowa Capitol. "They have lots of legislators who like them," Gingrich said. "They have a network in their states of organizers."
Gingrich's campaign also was dispatching former Oklahoma Rep. J.C. Watts to Iowa to meet with privately with GOP leaders and the media in an attempt to stabilize the campaign.
The spat over ads has dominated the GOP campaign in recent days as Gingrich and Romney, who is touring New Hampshire by bus, endeavored to fit in as much face time with voters as possible before Christmas.
On Tuesday, both candidates criticized the campaign finance system that has allowed groups like Restore Our Future to thrive. Romney called it "a disaster" and Gingrich described it as "a nightmare." But both benefit from so-called super PACs.
Romney also refused to urge the group backing him to halt its attacks, citing federal law that prohibits contact between his campaign and Restore Our Future. He also declined to disavow the ads.
"If we coordinate in any way whatsoever, we go to the big house," Romney said on MSNBC.
Gingrich later read Romney's remarks for reporters and then labeled them "baloney." Said Gingrich, "His comments are palpably misleading, clearly false and are politics at its worst form."
The ad standoff comes as Gingrich has lost ground in Iowa and elsewhere in the face of attacks by the Romney-aligned super PAC and others, including Texas Rep. Ron Paul. The ads have knocked Gingrich off message just as he's seeking to make his closing argument to Iowa voters.
With Gingrich flailing, Romney took on Obama in a speech Tuesday accusing the president of deepening the economic crisis and backing policies that will redistribute wealth instead of creating equal opportunity for people to do well.
Polls show Romney, Gingrich and Paul in contention for the lead in Iowa and elsewhere.
Paul, the blunt-spoken Texas congressman, was campaigning Wednesday in Iowa, along with other candidates in the field. The race there remains unpredictable, as voters weigh electability against conservative credentials.
The bickering over negative ads has highlighted the role of super PACs, independent groups that may accept unlimited donations but are not supposed to directly coordinate with candidates. Such groups have sprung up to support every serious Republican candidate following a U.S. Supreme Court decision last year that said individuals, unions and corporations can donate unlimited sums of money to outfits advocating the election or defeat of candidates.
Two pro-Gingrich groups have started raising money and Gingrich's longtime aide Rick Tyler just signed on with one of them.
Romney's supporters, however, have had a yearlong head start in raising money. Restore Our Future is slated to spend roughly $3 million on ads, most of which paint Gingrich as an ethically-challenged Washington power broker.
Gingrich, who trails Romney badly in fundraising, said he would disavow any group that runs negative ads on his behalf.
In a sign of his fundraising and organizational deficiencies, Gingrich was rushing home to Virginia later Wednesday to help ensure he has the needed signatures to get on the ballot there.