John Kerry had just pumped up a huge crowd in downtown West Palm Beach, promising to make the state a battleground for his quest to oust President Bush, when a local television journalist posed the question that any candidate with Florida ambitions should expect:

What will you do about Cuba?

As the presumptive Democratic nominee, Kerry was ready with the bravado appropriate for a challenger who knows that every answer carries magnified importance in the state that put President Bush into office by just 537 votes.

''I'm pretty tough on Castro, because I think he's running one of the last vestiges of a Stalinist secret police government in the world,'' Kerry told WPLG-ABC 10 reporter Michael Putney in an interview to be aired at 11:30 this morning.

Then, reaching back eight years to one of the more significant efforts to toughen sanctions on the communist island, Kerry volunteered: ``And I voted for the Helms-Burton legislation to be tough on companies that deal with him.''

It seemed the correct answer in a year in which Democratic strategists think they can make a play for at least a portion of the important Cuban-American vote -- as they did in 1996 when more than three in 10 backed President Clinton's reelection after he signed the sanctions measure written by Sen. Jesse Helms and Rep. Dan Burton.

There is only one problem: Kerry voted against it.

Asked Friday to explain the discrepancy, Kerry aides said the senator cast one of the 22 nays that day in 1996 because he disagreed with some of the final technical aspects. But, said spokesman David Wade, Kerry supported the legislation in its purer form -- and voted for it months earlier.

The confusion illustrates a persistent problem for Kerry as Republicans exploit his 19-year voting history to paint the Massachusetts senator as a waffler on major foreign-affairs questions such as the Iraq war, Israel's security barrier and intelligence funding.

Cuba policy is particularly treacherous for Kerry because Florida's nearly half-million Cuban-American voters could be pivotal in awarding the state's 27 electoral votes. And Republicans are preparing to unleash a wave of publicity designed to portray Kerry's new toughness as an election-year conversion from a career of liberal positions on Cuba.

Speaking to reporters Saturday after a meeting of senior Florida Republicans about increasing Hispanic turnout this year, Lt. Gov. Toni Jennings predicted that Kerry's voting record on Cuba would ''haunt'' him in the coming months.

OTHER VULNERABILITIES

Kerry will also rue past votes supporting loosened restrictions on travel and cash ''remittances'' that Cubans are allowed to send back to the island, Republicans said. They point to a 2000 Boston Globe interview in which Kerry called a reevaluation of the trade embargo ''way overdue'' and said that the only reason the United States treated Cuba differently from China and Russia was the ``politics of Florida.''

Republicans say they can increase Hispanic voter turnout in Florida from the 2000 levels, when outrage over the Clinton administration's decision to return Elián Gonzalez to his father in Cuba helped Bush crush then-Vice President Al Gore among Cuban Americans.

''Kerry is much softer on Castro than Al Gore was,'' Ken Mehlman, Bush's campaign manager, said in an interview.

Saturday's meeting came as GOP strategists worry about Bush's vulnerability on Cuba after months of criticism from some exile leaders who say Bush has failed to deliver on campaign promises to crack down on Castro.

One recent poll showed that three in four Cuban Americans planned to vote for Bush again -- but that a substantial number are concerned about his handling of Cuba policy.

Democratic strategists hope that such skepticism of Bush gives Kerry a foothold. But they acknowledge that a Democrat with Kerry's record is not likely to score points on Cuba policy among single-issue voters.

Some Cuban Americans, however, may be more flexible if they are equally skeptical of Bush and Kerry on the promise to foster reforms in Cuba. Strategists think they could be convinced by Democratic arguments on domestic matters such as jobs, healthcare and education.

''If they don't believe Bush on Cuba, then they certainly aren't going to believe someone who is new on the scene like Kerry,'' said Democratic pollster Sergio Bendixen, who is advising the centrist New Democrat Network on a new ad campaign targeting Hispanic voters. ``Cuban Americans don't believe anybody on Cuba policy, not Democrats or Republicans.''

Nevertheless, as Kerry fought for his party's nomination and began eyeing a Florida strategy, his language on Cuba morphed.

The first shift was evident in August, when Kerry told NBC's Tim Russert that he was not in favor of lifting sanctions. ''Not now,'' he said. ``No.''

Days later, in an interview with The Herald, Kerry offered a more textured explanation of his position, embracing ''humanitarian'' travel and other exchanges with the island to curb ``the isolation that in my judgment helps Castro.''

HE STRUGGLES

But there are also constant reminders that Kerry struggles with the complexities of Cuba. Asked in the Herald interview last year about sending Elián back to Cuba, Kerry was blunt: ``I didn't agree with that.''

But when he was asked to elaborate, Kerry acknowledged that he agreed the boy should have been with his father.

So what didn't he agree with?

''I didn't like the way they did it. I thought the process was butchered,'' he said.

And when he was asked last week during a town hall meeting in Broward County about immigration policies that allow Cuban migrants to remain if they reach land but do not give the same rights to Haitians and others who travel to Florida, he appeared to grasp for an answer.

First, he said all migrants have a right to make their case for asylum. Then, as if anticipating his weaknesses, Kerry turned the conversation back to the embargo, pledging that he would not support lifting sanctions.

''I haven't resolved what to do,'' he said, seeming to reflect on the full scope of Cuba concerns. ``I'm going to talk to a lot of people in Florida.''

Herald staff writer Lesley Clark and researcher Gay Nemeti contributed to this report.