A raft of new polls on Florida's GOP presidential primary all seem to agree, says Nate Silver in The New York Times: "Unless there is a major glitch, Mitt Romney will beat Newt Gingrich" in Tuesday's critical primary. The former House speaker enjoyed a poll surge after his come-from-behind win in the South Carolina primary. But now, Romney has regained a solid double-digit lead in the Sunshine State. "Romney's sitting in the driver's seat," says Lee Miringoff of the Marist Institute, whose latest NBC/Marist poll has Romney ahead of Gingrich by 15 points, 42 percent to 27 percent. What turned the race around so dramatically? Here, six theories:

1. Romney renewed his focus on destroying Gingrich
After getting trounced by Gingrich in South Carolina, Team Romney hatched a plan, say Jim Rutenberg and Jeff Zeleney in The New York Times: "Make Newt mad and Mitt meaner." They unleashed a "blistering and unrelenting series of attacks," many delivered by a newly aggressive Romney himself, and used "all the visible and invisible tactics of political warfare" to paint Gingrich as an "erratic, unreliable Washington insider." Romney and his allies crushed Gingrich and his allies in the ad war, outspending them 4-to-1, or about $17 million to $5 million. "It not about winning here anymore," a Romney staffer tells BuzzFeed's Zeke Miller. "It's about destroying Gingrich — and it's working."

2. And Mitt's Freddie Mac attack was deadly
Romney's biggest win was in the "Bain vs. Freddie" fight, says Alexander Burns at Politico. Mitt's lucrative career at Bain Capital was an albatross in South Carolina, but in Florida, about 75 percent view it positively versus 13 percent who view it negatively. And while Gingrich failed to make Bain an issue, Romney hammered him over his past consulting for Freddie Mac, blaming the federal mortgage giant —and, indirectly, Gingrich — for Florida's glut of foreclosures. More than half of Florida's GOP voters frown on Newt's Freddie Mac work.

3. Gingrich flubbed the debates
"Newt also hasn't been helping himself," says Alexis Garcia at Pajamas Media. "After dominating the South Carolina debates," he "committed a series of unforced errors" in the two Florida debates, turning in lackluster performances and talking about moon colonies when voters care about jobs and houses. Romney also sharpened his debate game, with the help of a new coach, Brett O'Donnell, and a crack opposition-research team. The Florida debates "blew up the foundation for Newt's campaign," says Hugh Hewitt at his blog. Voters liked him because he promised to "thrash President Obama in the debates," but losing to Romney shattered that myth.

4. Romney's surrogates carved up Newt
"It shouldn’t be underestimated how much the Romney operation has managed to get into Gingrich's head," says Reid Epstein at Politico. The Romney team realized that direct attacks throw Newt off his game, so they sent their deep bench of prominent surrogates — Sen. John McCain (R-Ariz.), Reps. Connie Mack IV (R-Fla.) and Jason Chaffetz (R-Utah), and Puerto Rico Gov. Luis Fortuño — to crash Gingrich rallies or attack him on the stump. Mitt even got some crucial "non-endorsement endorsements" from GOP heavy-hitters Jeb Bush and Sen. Marco Rubio (R-Fla.), whose "slapdowns of Gingrich's attacks" on Romney worked to Mitt's advantage.

5. The conservative media also ripped into Newt
Last week was pile-on-Gingrich week in the conservative press — with a little help from the influential Drudge Report. In the National Review, The American Spectator, and other influential conservative publications, "Gingrich comes off looking like a dangerous, anti-Reagan, Clintonian fraud," say Jim VandeHei and Mike Allen at Politico. "It's as if the conservative media... decided Gingrich is for real, and they need to come clean about the man they really know before it's too late."

6. Florida's elderly voters like Romney's family values
The "phenomenal shift in the polls" in Florida is actually pretty easy to explain, says Robert Stacy McCain at The Other McCain: "Your grandma loves Mitt Romney," and "there are lots of Republican grandmas in Florida." Romney is much better looking that Gingrich — "the tall, lean multimillionaire entrepreneur with dark hair and chiseled features" versus "the pudgy intellectual" — but his bigger selling point to grandma is his "old-fashioned 'family values' conservatism." When Romney talks about how he's still married to his high-school sweetheart, he doesn't even have to mention that "Newt is on Wife No. 3, with whom he had an affair while still married to Wife No. 2."