TAMPA, Florida (Reuters) - Rising Republican Newt Gingrich and rival Mitt Romney squared off on Monday at a debate that will help determine which of them has the best shot at winning the pivotal Florida presidential primary on January 31.
Stung by Gingrich's convincing victory in South Carolina on Saturday, Romney desperately needs a good debate performance to help restore momentum for his campaign.
Romney has fought back against Gingrich by drawing attention to Gingrich's record as a Washington insider and former speaker of the U.S. House of Representatives who left office under an ethical cloud.
After stumbling in the last debate in South Carolina when pressed about his tax records, the former Massachusetts governor promised to release two of his annual tax returns.
But he called on Gingrich to disclose his contract for the government-sponsored mortgage financing giant Freddie Mac, for which Gingrich made $1.6 million.
Shortly before the debate, Gingrich's former consulting firm released a contract Gingrich signed with the company in 2006, but it shed little light on what Gingrich was hired to do. The document called for a $300,000 retainer and $25,000 in fees monthly for the year.
Gingrich staunchly denies his work for the mortgage giant made him a lobbyist, but Romney insists he was, making his case the Gingrich is a creature of Washington.
"If it walks like a duck and quacks like a duck, it is a duck," Romney said.
The issue has particular resonance in Florida, one of the states hardest hit by the collapse of the U.S. real estate market, helping to contribute to a state unemployment rate of 9.9 percent, above the national average.
Florida's primary may play a huge role in determining who becomes the Republican nominee to oppose Democratic President Barack Obama's re-election bid in November.
Gingrich trounced the former Massachusetts governor in South Carolina's Republican primary, based partly on a series of strong debate performances. Aiming for another on Monday, he called Romney's attacks desperate.
"It used to be pious baloney; now it's just desperate baloney," he quipped. "As president, he'll be able to open a delicatessen."
New opinion polls show that Gingrich has already jumped into the lead in Florida.
The tense back and forth between the pair presaged a potentially bruising debate. The remaining two candidates, Texas Congressman Ron Paul and former Pennsylvania Senator Rick Santorum are seeking to make a mark after finishing far behind in South Carolina.
The contest, sponsored by NBC, National Journal and the Tampa Bay Times, is the 18th of the 2012 election cycle, and the first of two debates this week. A second is scheduled for Jacksonville on Thursday.
A Romney victory in Florida would blunt Gingrich's surge and restore the luster of his campaign. Gingrich wants to deliver what he has called "the knockout punch."
Gingrich has used the debates to his advantage, helping him rise from a bitter fourth-place finish in Iowa to victory in South Carolina.
When his ex-wife told ABC News last week that Gingrich had sought an "open marriage," Gingrich turned questions about it into an attack on the news media that thrilled conservatives and helped undecided voters swing his way.
But Romney has waged successful attacks on Gingrich. An ad campaign run by the Romney team and an outside group that backs him lampooned Gingrich in Iowa and knocked him out of the front-runner position.
Before the debate, a crowd of about 100 Occupy Wall Street protesters gathered outside the debate hall, shouting chants including, "We are the 99 percent."
Additional reporting by Steve Holland; Writing by Steve Holland and Patricia Zengerle; Editing by Peter Cooney