TAMPA, Fla. — A newly aggressive Mitt Romney charged in campaign debate Monday night that Newt Gingrich "resigned in disgrace" from Congress after four years as speaker and then spent the next 15 years "working as an influence peddler" in Washington.
Gingrich shot back that Romney's attacks were riddled with falsehoods, and he referred to statements by two men who ran against Romney in 2008 in contending the former Massachusetts governor "can't tell the truth."
The clash occurred in the opening moments of the first of this week's two debates before the Jan. 31 Florida primary.
Gingrich trounced Romney in last Saturday's South Carolina contest, an upset that reset the race to pick a rival to President Barack Obama in the fall.
Former Pennsylvania Sen. Rick Santorum and Texas Rep. Ron Paul shared the debate stage.
Asked if he could envision a path to the nomination for himself, Santorum said the race has so far been defined by its unpredictability. He conceded he had been defeated for re-election in 2006 in Pennsylvania but said the party lost the governorship by an even bigger margin than his own defeat.
"There's one thing worse than losing an election and that's not standing for the principles that you hold," he said, a comment he frequently makes while campaigning in an attempt to question Romney's commitment to conservatism.
Paul sidestepped when moderator Brian Williams of NBC asked if he would run as a third-party candidate in the fall if he doesn't win the nomination. "I have no intention," he said, but he didn't slam the door.
The polls post-South Carolina show Gingrich and Romney leading in the Florida primary. That and the former speaker's weekend victory explained why the two were squabbling even before the debate began.
Romney began airing a harshly critical new campaign ad and said the former House speaker had engaged in "potentially wrongful activity" with the consulting work he did after leaving Congress in the late 1990s.
Gingrich retorted that Romney was a candidate who was campaigning on openness yet "has released none of his business records."
He followed up two hours before the debate by arranging the release of a contract his former consulting firm had with the Federal Home Loan Mortgage Corp. for a retainer of $25,000 per month in 2006, or a total for the year of $300,000. The agreement called for "consulting and related services."
Despite Romney's attempts to call Gingrich a lobbyist, the contract makes no mention of lobbying.
Increasingly, the race for the nomination appeared to be a two-way competition between the former Massachusetts governor and the one-time speaker of the House.
After relying on allies to make most of the attacks on his rivals earlier in the campaign, Romney unleashed a commercial that went straight at Gingrich.
"While Florida families lost everything in the housing crisis, Newt Gingrich cashed in," the TV ad says, noting that the former speaker made more than $1.6 million working for Freddie Mac. "Gingrich resigned from Congress in disgrace and then cashed in as a D.C. insider."
Gingrich never registered as a lobbyist, but said he was a consultant for Freddie Mac, the federally backed mortgage company that played a significant role in the housing crisis.
It remains to be seen if Romney can effectively use his newly aggressive stance on the debate stage, a forum in which Gingrich has excelled so far. Underfunded and overmatched by Romney's massive ground game across the country, Gingrich has relied upon strong debate performances to build support.
It appears Romney has brought in outside help to improve his debate technique.
Veteran debate coach Brett O'Donnell was spotted at a Romney campaign stop on Monday. He previously advised President George W. Bush and GOP nominee John McCain and was a senior adviser and speech writer for Michele Bachmann's abbreviated campaign.
Gingrich showed no signs of backing down.
During an appearance on ABC's "Good Morning America," he referred to Romney as "somebody who has released none of his business records, who has decided to make a stand on transparency without being transparent." After initially balking, Romney is set to release personal tax records on Tuesday