Gingrich and Romney dash for the finish line

Florida Republicans head to the polls today for a primary election that could decide the party's nominee to run against President Barack Obama in November.

In a see-saw battle the past two weeks, Newt Gingrich watched the momentum he brought to Florida after his win in South Carolina evaporate and his leads in polls transform into double-digit leads for Mitt Romney.

As of late Monday, the RealClearPolitics website average of all polls in the race showed Romney with 42 percent to Gingrich's 29 percent, 13 percent for Rick Santorum and 10 percent for Ron Paul.

If the voting produces a big lead for Romney, experts say, it may effectively end the contest for the nomination, although both Gingrich and Ron Paul have vowed to keep campaigning until the convention in Tampa in August.

"If Romney wins big, it will be tough to stop him: Florida will have been instrumental in resurrecting the likely nominee," said University of Texas political scientist Bruce Buchanan.

A narrow Romney win, however, could mean a long fight.

"If Romney wins by less than 10 points, Gingrich can fight on with some confidence that he'll have the resources to make it through at least to Super Tuesday," said Dan Schnur, a former GOP political strategist who now runs the Jesse M. Unruh Institute of Politics at the University of Southern California.

As the race closed, Gingrich roused crowds with news of a few late polls suggesting he had moved back to within single-digit striking distance of Romney in Florida.

Both candidates scrambled across the state Monday seeking exposure in as many media markets as possible, particularly the Tampa Bay area, home to one-quarter of the state's roughly 4 million Republicans.

Romney hit Jacksonville, The Villages and a rally in Pioneer Park in Dunedin and planned an election night gathering at the Tampa Convention Center.

Gingrich's fly-around included an airport rally in Tampa along with Jacksonville, Pensacola and Fort Myers, finishing in Orlando, location of his state headquarters.

He planned a stop in Plant City for today before an election night rally in Orlando.

Santorum and Paul, meanwhile, both campaigned in other states Monday.

Gingrich repeated his previous promise to ask the House and Senate to stay in session after he is elected to repeal the Obama health care law. He said he also would push Congress to repeal the Dodd-Frank Wall Street Reform and Consumer Protection Act, passed after the financial crisis of 2007-08, and the Sarbanes-Oxley Act of 2002, a package of corporate reforms to ensure financial disclosure and combat corporate and accounting fraud.

Gingrich said the laws are hurting the economy and stifling entrepreneurism.

Traveling with Gingrich were Michael Reagan, eldest son of the late President Ronald Reagan, and Herman Cain, the businessman who dropped out of the Republican presidential race last year, then endorsed Gingrich.

The boisterous Tampa crowd interrupted Gingrich several times with chants of "Newt, Newt" and "Newtron Bomb." One audience member presented the former speaker and his wife a graphic art poster comparing Obama's health care plan with a similar law Romney signed when he was Massachusetts governor. The poster said, "Make no mistake, Romney Care is Obama Care."

Mike Murphy of Palm Harbor said he's been a Gingrich fan for years.

"I believe he's going to stand up for conservative principles, and I believe he can beat Obama in a debate," Murphy said before the speech.

Another fan, Tony Incardoni, said he had hoped Gingrich would run for president soon after he left Congress in 1999.

"He's a natural leader," Incardoni said. "What gets me going the most is he's not pandering to the left. He understands that more than anybody."

Romney, meanwhile, campaigned with the confidence and swagger of a front-runner.

"I know the speaker's not real happy," he told a crowd at Dunedin's Pioneer Park on Monday, "flailing around a bit trying to go after me for one thing after another. … It's painful to watch."

In Jacksonville, Romney ridiculed Gingrich: "Send him to the moon," he said, mocking Gingrich's proposal to build a moon colony.

He was accompanied by state Attorney General Pam Bondi, Agriculture Commissioner Adam Putnam, U.S. Rep. Connie Mack of Fort Myers and Mack's wife, Rep. Mary Bono of California.

"The idea of the moon as the 51st state," subject of past legislation Gingrich sponsored, is "not one that's come to my mind," he added.

Gingrich increasingly has portrayed the race as a battle between the Republican "establishment" and Romney, an agent of the status quo, and conservative change agents.

"My hope is that gradually conservatives will come together and decide that a Newt Gingrich conservatism is better than Mitt Romney's liberalism," he said in an ABC news interview.

His allies have urged Santorum to get out of the race to clear the way for conservatives to consolidate support behind Gingrich.

"I think he's going to find this a long campaign," Gingrich said of Romney.

In the closing days of the race, the back-and-forth between the two has become increasingly bitter and personal.

Gingrich has questioned Romney's character and honesty in a new ad saying, "What kind of man would mislead, distort and deceive just to win an election? This man would. Mitt Romney."

Romney has fired back with an ad using a video clip of Tom Brokaw announcing the House Ethics Committee decision to reprimand and fine Gingrich for violations while he was speaker.

Spending by the campaigns and the independent super-PACs backing each candidates isn't known for sure, but estimates by independent watchdog organizations including ProPublica and the Wesleyan Media Project agree that most of the flood of ads is coming from the super-PACs.

According to those estimates, Restore Our Future, backing Romney, has spent $10.8 million, with an additional $4 million spent by the Romney campaign.

The Gingrich campaign and Winning Our Future, backing Gingrich, have spent about $4.3 million.

"That's why they're trying to carpet-bomb us here in Florida," said former Gingrich aide Rick Tyler, who runs the pro-Gingrich political action committee Winning Our Future. "They're trying to end this thing. But it's not going to end."