MIAMI - On a hot and humid January day here, in a city that feels a million miles away from Des Moines or Manchester, Republican presidential hopefuls Mitt Romney and Newt Gingrich, for the first time in the campaign, spent much of their day on the trail trying to woo Latino voters.

At a Univision forum Wednesday,  Gingrich ripped Romney for an immigration policy that he called "a fantasy" from "a world of Swiss bank accounts and Cayman Island accounts and … $20 million a year of no work." Hours later Romney hit back, admonishing Gingrich for barbs that he deemed "unbecoming of a presidential candidate" and emphasizing that "the immigrant population in this country has created great vitality in our economy as well as our culture."

Looks like we're not in Iowa anymore.

For much of the GOP race so far, the candidates' rhetoric toward Latinos has been nothing short of inflammatory, from Herman Cain joking that as president he would build an electric fence along the Mexican-U.S.  border to Romney touting the endorsement of anti-immigration activist Kris Kobach. In the early days of the Republican primary, that strategy may have made sense, in a way, if  it could ever be suggested that alienating the country's fastest-growing voting bloc ever made sense. The Hispanic population in early-voting states like Iowa and South Carolina hovers around 5 percent, while in New Hampshire it's less than 3 percent. In addition, Latinos tend to vote Democrat, further reducing their relevance to the GOP candidates.

But with the Florida primary coming up Tuesday, and Romney and Gingrich locked in a virtual dead heat here, it's time to court the Latino vote.

According to data from the Florida Division of Elections compiled by the Pew Hispanic Center, Latinos make up 13.1 percent of the state's 11.2 million registered voters. Nearly 1.5 million Latinos are registered to vote here, and as recently as 2006 more than half of them - now around 450,000 - are registered Republican, constituting 11 percent of all GOP registered voters.

Simply put, Hispanics matter here - and in a big way. Just ask none other than Romney himself. In 2008, Romney's rival, Sen. John McCain , won 54 percent of the state's Hispanic vote, with only 14 percent going to the former Massachusetts governor. Romney lost the state, and his party's nomination.

Five days before this year's primary, Romney appears to be faring much better. According to a new poll conducted by Latino Decisions for ABC News and Univision, Romney has a whopping 26-point lead over Gingrich among Latino Republicans in Florida, 49 percent to 23 percent.

If you've been following the race closely, you might wonder how that's possible. After all, wasn't it Romney who campaigned with Kobach and who vowed that if elected he would veto the Dream Act, the Democrats' bill to provide a path to citizenship for some children of illegal immigrants who attend college in the U.S. or serve in the military? And wasn't it Gingrich who voiced the most moderate stance of all Republican candidates on immigration, who held Latino town halls in New Hampshire, who beefed up his Hispanic outreach efforts long before the race hit Florida?

From Iowa to New Hampshire to South Carolina, in state after state, numerous Latinos have refused to vote for Romney because of his immigration policy. In Des Moines, businessman Juan Rodriguez said he would not support Romney because of the candidate's comments on immigration. The following week in Goffstown, N.H., Esteban Lopez, who will vote for the first time in the general election later this year, said he would not back Romney either. In South Carolina, college student Nivardo Vivar said the same.

The answer is simple: Latinos in Florida are not like Latinos in the rest of the country.

Unlike in states like Nevada, Arizona and Colorado, most of Florida's Latino population does not come from Mexico. The state's most influential Latino-American voting bloc comes from Cuba, and Cubans tend to split from other Latinos on the  issue of immigration. Cuban immigrants are granted sanctuary in the United States if they reach the country, making them immune to Republican policies that show little tolerance for undocumented immigrants. An illegal immigrant from Mexico, for instance, would be thrown out of the country if Romney's immigration policies took hold, but Cubans have no such fears.

Earlier this month, Romney hit Florida airwaves with a Spanish-language ad   titled "Nosotros," meaning "us." The ad included a slew of key Florida Republicans of Cuban descent who back Romney, such as Rep. Ileana Ros-Lehtinen, Rep. Mario Diaz-Balart  and former Rep. Lincoln Diaz-Balart.

Not included was the newest hotshot, Sen. Marco Rubio, widely expected to be one of the top candidates for the No. 2 slot on the eventual Republican ticket. Rubio, a Cuban-American elected to the U.S.Senate in 2010, opposes giving amnesty to undocumented workers  but enjoys widespread backing among the Cuban community in south Florida. The senator has promised not to endorse any candidate until the party has a nominee, at which point he will campaign for that nominee. But in recent days he has sided with Romney over a controversial Gingrich radio ad that branded Romney as "anti-immigrant." Rubio's public rebuke of Gingrich prompted the former House speaker to pull the spot.

So far it has all added up to strong support for Romney among Cuban-Americans here, a dramatic reversal from 2008 when McCain enjoyed 52 percent of the group's support, compared with 13 percent for Romney.

Puerto Ricans are the second-most prominent faction of Florida Latinos. Like Cubans, Puerto Ricans, who are U.S. citizens,  do not have the same immigration concerns that the other Latinos have. And they are becoming more and more crucial: The Puerto Rican population has nearly doubled in the past decade. In recent elections, they have wavered from side to side, supporting Rubio as well as the state's former Republican Gov. Jeb Bush, but they backed Obama in 2008. Registered Puerto Rican voters in Florida favor Romney over Gingrich, but by a much slimmer margin than Cuban-Americans: only 22 percent to 12 percent.

Without much of a backlash from Florida Latinos for his immigration stance, Romney appears poised for a strong showing among this crucial voting bloc on Tuesday. But even if he emerges victorious in the primary and goes on to secure the nomination, Romney has work to do here for the general election .

According to the Latino Decisions poll, Romney trails President Obama 40 percent to 50 percent in a hypothetical general election matchup. Picking Rubio as his running mate, though, would provide a massive boost. Sixty  percent of Latino Republicans in Florida said they would be much more likely to vote Republican in November if Rubio was added to the eventual ticket. Fifty-six percent of Florida Latino Republicans said they currently had a very favorable impression of the senator.

Come fall, an estimated 12.2 million Latinos are set to vote, according to projections from the National Association of Latino Elected and Appointed Officials, and perhaps no state could prove more important than Florida. The Republican Party picked the Sunshine State to host its 2012 convention and the state will also host the final presidential debate, set for Oct. 22, at Lynn University in Boca Raton.

It's not lost on anyone, it seems, that in nine of the past 10 presidential elections, Florida - the state with the country's sixth-largest Hispanic population - has voted for the eventual victor.

Matthew Jaffe covers the 2012 campaign for ABC News and Univision.