ORMOND BEACH, Fla. — Mitt Romney is pressing reset.
After a crushing loss to Newt Gingrich in South Carolina, the former Massachusetts governor made clear Sunday that he plans to attack his chief rival's character, release his tax returns this week and try to right a campaign he acknowledged had been knocked off kilter.
"It was not a great week for me," Romney acknowledged during an interview on "Fox News Sunday."
Romney now turns to Florida at what is possibly the most critical moment of his campaign, after two weeks of sustained attacks from his opponents and a series of self-inflicted errors that erased any notion that he would be able to lock up the nomination quickly by winning this state's Jan. 31 primary.
"I'm looking forward to a long campaign," Romney said. "We are selecting the president of the United States. Someone who is going to face ups and downs and real challenges, and I hope that through this process, I can demonstrate that I can take a setback and come back strong."
Even if Romney does manage a victory here — his Florida campaign is by far the strongest of any in the GOP field, and he and his allies have been alone on the air for weeks — the race has become a two-way fight between him and Gingrich, the former House speaker with a huge dose of momentum.
And now Romney's team is girding for a long and costly fight for the party nod that extends well beyond Florida after Saturday night's shellacking in South Carolina that underscored the former Massachusetts governor's vulnerabilities and undermined his claims of becoming the inevitable Republican nominee.
Over the next 10 days, the candidates — including former Pennsylvania Sen. Rick Santorum and Texas Rep. Ron Paul — will meet twice on the debate stage, a venue where Gingrich has thrived in recent weeks and Romney has struggled some when pressed about questions about his wealth and private business experience. The debates — Monday in Tampa and Thursday in Jacksonville — present fresh opportunities for both breakout performances and mistakes.
Romney previewed his more aggressive posture and lines of attack toward Gingrich on Saturday night, saying: "Our party can't be led to victory by someone who also has never run a business and never led a state." He also argued, again without naming Gingrich, that "we cannot defeat that president with a candidate who has joined that very assault on free enterprise." Gingrich has attacked Romney's record running Bain Capital, a private equity firm.
But, behind the scenes, aides also indicated that Romney would go after Gingrich's character in Florida as a way to distinguish the father of five who has been married to the same woman for 42 years from his thrice-married rival. And the aides argued that the results in South Carolina don't indicate Republican primary voters everywhere are willing to overlook Gingrich's two divorces and acknowledged infidelity. Gingrich's second wife, Marianne, told ABC News in an interview aired Thursday that the former speaker asked her for an open marriage so he could continue having an affair with the House staffer who is now his third wife.
Publicly, Romney has refused to engage on the subject thus far, saying at a debate Thursday, "Let's get onto the real issues. That's all I got to say."
But Romney has started poking at Gingrich's character by raising questions about the ethics investigation against Gingrich in the 1990s when he was House speaker, and suggested that the former Georgia lawmaker was hiding something by refusing to release reams of documents he apparently gave to investigators back then.
Asked Sunday whether character would become an issue, Romney said: "No question."
"Leadership is the key attribute that people should look for in considering a president," Romney said, "and character is a big part of leadership, as is vision, sobriety, steadiness."
Romney's team also plans to contrast his experience as a governor and businessman with Gingrich's experience in Congress and his later work with former colleagues on behalf of businesses.
"It will really come down to someone who's offering Washington experience, congressional experience, K Street experience, versus a governor and a businessman," said Stuart Stevens, Romney's top strategist. "It will be a straight-up choice."
Romney, meanwhile, also is working to fix a key vulnerability — defensiveness over questions about his personal wealth, including money in funds in the Cayman Islands, a popular haven for international investment.
Under pressure to release his tax returns immediately, Romney reversed course and said he would release those documents for 2010 and an estimate for 2011 on Tuesday — months ahead of their April planned release.
The documents will lay out just how Romney, a multimillionaire many times over, makes his money and reveal his actual tax rate, which Romney estimated at about 15 percent.
New Jersey Gov. Chris Christie, a backer who had called on Romney to immediately release his returns,