Mitt Romney may be on his way to a decisive victory in the Florida GOP primary Tuesday, according to a new NBC/Marist poll.
Romney leads Newt Gingrich by 15 points, 42 percent to 27 percent in the crucial state. Rick Santorum is third with 16 percent, followed by Ron Paul with 11 percent. Just 4 percent said they were undecided.
"The bottom line in all this is Romney's sitting in the driver's seat going into Tuesday," said Lee Miringoff, director of the Marist Institute for Public Opinion at Marist College, who conducted the poll.
If Romney pulls off a victory of that magnitude, he could be on a glide path to the nomination. But there are warning signs for the Republican Party that the primary has taken a toll on Romney and the rest of the GOP field. Each of the candidates struggles in a general-election matchup with President Barack Obama in this swing state, especially with independents.
How Romney wins: Consolidates supporters, women
Romney beats Gingrich and the rest of the field by winning broadly across many subgroups -- those who are not Tea Party supporters (52 percent), those who are liberal or moderate (49 percent), make more than $75,000 a year (49 percent), identify as "conservative" (47 percent), and, in particular with women.
There was a stark gender gap between Romney and Gingrich. Women said they preferred Romney by 47-26 percent over Gingrich. The gap is closer with men, but Romney leads with them as well, 38-29 percent.
"He's winning both," Miringoff said, "but runs up the score among women."
Romney also does well enough with Tea Party supporters, splitting the vote with Gingrich. Gingrich leads among that group, 36 percent to 34 percent, with Santorum taking 22 percent. And, Romney runs even or leads Gingrich in the traditionally more conservative northern part of the state. In addition, more GOP primary voters said Romney represented their views on immigration than any other candidate.
Romney also leads among evangelical Christians, receiving the support of 34 percent, compared to 28 percent for Gingrich. Six-in-10 GOP primary voters said they believed Mormons are Christians. But even among those who say they don't believe so, Romney splits the vote with Gingrich. In 2008, born-again or evangelical voters made up 39 percent of the GOP primary in Florida, lower than the 60 percent who identified as such in Iowa and South Carolina.
Gingrich leads Santorum among "very conservative" voters 36 percent to 29 percent. Romney gets about a quarter of that group -- 24 percent.
But Gingrich would have a hard time arguing that a majority is voting against Romney, and that if Santorum were not in the race, he would win. When Santorum is removed from the equation, his vote splits off evenly between Romney and Gingrich -- and Romney leads Gingrich by an even wider 16-point margin, 49-33 percent.
Santorum is the only candidate to see a debate bounce. In the three days of polling (Wednesday through Friday), Santorum saw a five-point increase after the debate. He was also seen as the "true conservative" in the race -- 38 percent said so versus 18 percent for each Romney and Gingrich, and 16 percent for Paul. More voters also said they saw Santorum as the candidate who best represents the middle class.
Electability, being able to beat President Obama, mattered most to GOP primary voters -- and those voters chose Romney. That could be why a majority -- 55 percent -- said they wanted the nomination fight to be over quickly. Forty-three percent said they would like to see someone else run; just 52 percent said they were satisfied with the current crop of candidates.
"This speaks to a lack of enthusiasm," Miringoff said. "People are a little fatigued with the process."
Ad blitz: Importance of Super PACs
Florida's 50 delegates are winner-take-all, so the stakes are high for the front-runners. Reflecting the importance of the state, Romney, Gingrich and their allies are spending about $22 million statewide on TV and radio advertisements.
Romney's campaign and Restore Our Future -- the super PAC supporting him -- have blitzed the airwaves, outspending Gingrich and Winning Our Future -- the super PAC backing Gingrich -- 4-to-1, according to the Republican ad-buying firm Smart Media Group Delta.
Despite Gingrich's protestations labeling Romney as "totally dishonest" for his attacks, the ad spending has proved difficult to overcome.
Consider, according to the survey, that Gingrich's acceptability rating has taken a big hit from a month ago. In December, 65 percent said Gingrich was an acceptable choice to be the GOP nominee. In this poll, just 48 percent said so.
"It's the net effect of the negative ads," Miringoff said, adding, "Romney's been successful in raising Gingrich's negatives; Gingrich hasn't been able to do the same with Romney."
Romney is seen as the most acceptable candidate: 62 percent said so, just 11 percent said he's not. (Paul is the least acceptable – 45 percent said that.)
Without being able to match Romney's resources or knocking Romney off stride at the two debates prior to the primary, Gingrich has been unable to compete with the barrage of advertising -- in a state so large that TV and radio ads are key.
Importance of the early vote
More than 400,000 have already voted early in the Sunshine State -- about 20 percent of the 1.9 million who voted in the 2008 GOP primary. That number could rise to as high as 25 to 30 percent before Tuesday, Miringoff said.
That provides a big cushion for Romney, because he leads with early voters by 22 points, 49-27 percent. That could account for about five percentage points, Miringoff said.
"He has a bit of an insurance policy with those early voters," Miringoff pointd out.
With all these numbers, Gingrich's path is difficult to see.
"There's not much left for Gingrich," Miringoff said. "He's left without an identity. He needs another moment, and it's hard to imagine what that would be."
Romney, GOP struggle against Obama
Romney and rest of the candidates, however, continue to trail President Obama in Florida among all voters. Romney does best, but loses 49-41 percent, a point worse than a month ago.
As in the latest NBC News-Wall Street Journal poll, Gingrich fares the worst of the entire GOP field against Obama, worse even than Santorum or Paul. Obama beats Gingrich, 52-35 percent, a five-point wider advantage for Obama from December.
Obama, whose approval rating in Florida is 46 percent, has a lead over Romney, in large part, because of independents. Independents sided overwhelmingly with the president -- 50-36 percent over Romney, and by 20 points or more over Gingrich, Santorum and Paul.
"Obama does well, because independents have been scared away," Miringoff said. "If Romney locks up the nomination any time soon, he's going to have to pivot quickly to win back independents."