ORLANDO, Fla. (AP) — Mitt Romney, forced to prove his resilience after a stinging loss in South Carolina, is showing why the so-called Republican establishment thinks he has the best discipline, organization and campaign smarts to challenge President Barack Obama this fall.
The former Massachusetts governor turned in his best debate performance yet Thursday night, putting chief rival Newt Gingrich on the defensive from the opening minutes in Jacksonville, Fla., and never letting up for two hours. It was a striking change after two South Carolina debates in which Gingrich revived his own campaign with fiery populist and media-bashing zingers that made Romney appear pallid in comparison.
Romney hired a new debate coach after those events. He was considerably more aggressive in a debate Monday in Tampa.
Then on Thursday, he urged his supporters to pack the hall in Jacksonville for the debate aired by CNN. As soon as it started, he appeared more prepared, polished and focused than Gingrich, who curiously dropped the fire-breathing aggressiveness he had shown only hours earlier at a morning tea party rally.
In contrast to the rousing ovations that Gingrich, the former House speaker, had received in the two South Carolina debates, the Jacksonville audience seemed mostly on Romney's side.
"When I'm shot at, I'll return fire," Romney said moments after the debate ended. "I'm certainly no shrinking violet."
Many Republicans expect Tuesday's Florida primary to be close. And debate performances are only one part of the GOP presidential campaign. It also features millions of dollars in TV, radio and mail ads and heavy coverage of candidates' events by local news outlets.
This cycle's presidential debates, however, have drawn big audiences and played an unusually large role in shaping the campaign. Gingrich's feisty performances after his near-fatal finish in Iowa helped put him into strong contention with Romney.
Romney's performance Thursday will doubtlessly reassure many mainstream party members who see Gingrich as too mercurial and burdened by past political battles to make the strongest case against Obama.
"Romney took the right lesson from South Carolina: Keep your opponent down, don't let him back up," New Hampshire political scientist Dante Scala, who follows the contest closely, said on Twitter before the debate was half over.
Former Sen. Rick Santorum and Texas congressman Ron Paul also participated in the forum, although Paul is not actively campaigning in Florida. Santorum scored strong points by noting that both Gingrich and Romney have supported mandatory health insurance for individuals.
Santorum says that history weakens the two men's ability to challenge Obama on mandated health coverage. Santorum is struggling to compete in sprawling, expensive Florida, however, and he planned to return for a while to Pennsylvania on Friday.
Romney's performance in Jacksonville was by no means perfect. He said he didn't remember a Spanish-language radio ad that his campaign is airing against Gingrich. CNN's Wolf Blitzer assured him the ad was his, and Gingrich needled him about it.
Romney also spent long segments explaining that his millions of dollars in personal wealth are invested by a trustee who keeps the details private to avoid conflicts of interest. Such sound bites might hurt Romney in a general election, which draws independent and Democratic voters who are likely to be more skeptical of a millionaire's hired accountants and complex investing than are some Republican activists.
On balance, however, Gingrich's supporters are likely to look back on the CNN debate and wonder what happened to the fire that boiled inside their champion Thursday morning, when he accused Romney of lies and gross hypocrisy.
One moment was especially telling. Blitzer asked Gingrich to explain his criticism of Romney's investments in, among other places, Swiss banks and Cayman Island accounts. Those locations sometimes are used to avoid U.S. taxes.
Gingrich, who often delights conservative crowds by lecturing or berating reporters, said the question was inappropriate for a presidential debate. Blitzer pressed on, saying Gingrich had made serious allegations about the investments, which Romney defends as above-board.
In what seemed a peace offering, Gingrich turned to Romney and said, "You want to try again?"
Romney answered with a verbal smack. "Wouldn't it be nice if people didn't make accusations somewhere else that they weren't willing to defend here?" he said coldly.
The moment was reminiscent of Tim Pawlenty's refusal in an August debate to repeat a sharp criticism he had recently made of Romney. Pawlenty, a former Minnesota governor, soon dropped out and endorsed Romney.
Romney seemed determined to attack Gingrich at the first opportunity, even at the risk of strained indignation. He pounced when Gingrich, pressed on whether Romney is "the most anti-immigrant candidate," said blandly, "I think, of the four of us, yes."
"That's simply inexcusable," Romney retorted.
Immigration is a sensitive issue among Florida's Hispanic voters. Gingrich recently dropped an ad that called Romney anti-immigrant, at the request of Sen. Marco Rubio, R-Fla., whose parents are from Cuba.
Romney said Gingrich's comments were "the kind of over-the-top rhetoric that has characterized American politics too long." He said Gingrich should apologize.
Gingrich regained some of his populist groove late in the debate.
"One of the reasons I am running is, there has been an increasingly aggressive war against religion, and in particular against Christianity in this country, largely by a secular elite and the academic, news media and judicial areas," he said. "It's important to have some leadership that stands up and says, 'Enough.'"
The campaign question for Gingrich is: Did he do enough in his two debate opportunities in Florida to maintain his eye-popping momentum from South Carolina?
EDITOR'S NOTE — Charles Babington covers politics for The Associated Press.