Updated

For nearly a decade, Republican presidential candidates have counted on Florida's Cuban-American community to win the state and, with it, the presidency.

This year's hopefuls are again making the rounds in Little Havana and on Miami's Spanish-language radio, mixing criticism of Fidel Castro's Cuban regime with scathing comments about Venezuelan President Hugo Chavez.

But this once fail-safe plan has become more risky as Florida's increasingly diverse Hispanic community no longer guarantees a monolithic vote. Of the state's estimated 3 million Hispanics, Cubans represent a third. Puerto Ricans and Mexicans, more traditionally Democratic voters, make up another third, and Central and South Americans round out the group.

Meanwhile, Democrats, who after former President Clinton all but ceded the Cuban-American vote, are courting the community with renewed vigor while also using Florida as a platform to reach out to Hispanics nationwide.

The eight Democratic candidates will participate in a live forum Sunday at the University of Miami sponsored by the Spanish-language Univision Network. The televised forum, with the candidates' answers translated simultaneously from English to Spanish, is aimed at the nation's more than 34 million Hispanics, underscoring the candidates' recognition of this demographic shift.

On the Republican side, only John McCain agreed to attend Univision's now-canceled GOP forum. His rivals cited scheduling conflicts, though Univision executives say they are in talks with the candidates to reschedule the event.

The Univision forum is the third nationally televised Hispanic event in Florida in the last six months that the top Democratic candidates have attended, and the third that major Republican candidates have skipped.

Instead, Republicans are focused on their core Florida constituencies -- religious conservatives, retired and active military members and Miami Cubans. They haven't focused as much on Orlando's Puerto Ricans, the state's Mexican-Americans or other Hispanics.

That makes sense for now, said Dario Moreno, a political science professor at Florida International University, but will likely change for the general election. Among likely Hispanic voters, Republicans still outnumber Democrats by 10 percent in Florida, but the Democrats' numbers are rising and the GOP's remain flat.

"You have to look at two different strategies. One is the primary, and as far as the Republicans, it's really concentrated in Miami, because that's where the majority of (Hispanic) Republican primary voters are," Moreno said.

Rudy Giuliani has sought support among state Republican leaders and in areas such as the heavily Cuban-American Miami suburb of Hialeah.

Mitt Romney also has made repeated visits to Little Havana, including the requisite stop at Versailles restaurant, where Cuban-American leaders have long closed deals over sweet espresso and ham-filled croquetas.

He also has emphasized his broader Latin-American policy credentials, including trips to the region when he was a venture capitalist, in an effort to reach out to other voters.

Giuliani, whose law firm once represented a subsidiary of Venezuela's national petroleum company, and Romney also have criticized the links between Venezuela's Chavez and Cuba's Castro.

That argument resonates both with Cuban exiles and Florida's burgeoning and well-heeled Venezuelan-American community.

Still, it may not play as well with the broader Hispanic community, which is more concerned about mainstream issues such as the Iraq war, the economy and affordable housing.

"They're still delivering a message to segmented sectors of the electorate. When you go on Univision, you are addressing the entire community, from New York to California," Moreno said. "You're not just addressing the Venezuelan leaders or the Colombian leaders."

And then there is immigration.

All the Republican candidates but McCain opposed a bill that would have provided a path to legalization for the nation's nearly 12 million illegal immigrants, many of them Hispanic.

Yet Democrats still face their own hurdles. The Democratic National Committee recently banned the presidential candidates from campaigning here to punish Florida for leapfrogging its primary to Jan. 29.

Until then, some of the leading Democratic hopefuls had been trying to woo the state's Hispanics -- but like Republicans, their main focus has been on more moderate Cuban-Americans.