John McCain threw up his Florida fire wall yesterday: a million Cuban Americans who see Barack Obama as a combination of Fidel Castro, Hugo Chávez, and any other Latin leader who ever nationalised a business.

In the streets of Miami's Little Havana, which McCain visited yesterday, there was one word for the kind of change promised by Obama. "Comunismo," said Michael Garcia, 30, the son of Cuban emigres who works at his family-owned accounting business.

"I shouldn't have to pay more taxes because I work harder than other people," he said. "The things that Obama say scare me because that's everything that Fidel said. These things are associated in my mind with going down the path to communism."

McCain, who is fighting to hang on to the pivotal state, has tried for two weeks to tap into fears that Obama would raise taxes for business owners, using the story of Joe the Plumber, the Ohio man who confronted the Democrat about his plan to "spread the wealth around".

But nowhere perhaps has McCain found a more willing audience for his story about Joe the Plumber than south Florida, the heartland of Cuban emigres - where he is known locally as "Pepe el plomero".

Cuban support is crucial to McCain if he is to hold Florida in Tuesday's elections, and block Obama from winning the White House. Here, in the traditional Republican enclave of Little Havana, even the faintest whiff of socialism revives memories of exile from Castro, a psychology McCain played on yesterday. "Senator Obama is running to be Redistributionist in Chief. I'm running to be Commander in Chief," he told a crowd of a few hundred at a local lumber yard. "Senator Obama is running to spread the wealth. I'm running to create more wealth. Senator Obama is running to punish the successful. I'm running to make everyone successful."

In the small, tidy homes of Little Havana, lawn campaign signs warn that an Obama presidency would be the first step to communism. Many of the McCain supporters in the lumberyard yesterday see Obama as practically a clone of Castro.

"Obama is saying 100% the same things that Castro was saying before 1959," said Nerty Piscola who left Cuba as a teenager in 1969. "It sounds good. Many people want to be equal, but the result is that everyone is equal and everyone is poor."

The fears run even deeper among those who were adults at the time of the revolution. "If Obama takes power you are going to see all the people going to the fields to cut sugar cane," said Lazaro de Jesus, a sign painter.

In recent years, Florida's Cuban Americans have been reinforced in their anti-socialist, anti-Democratic views by a new wave of Spanish-speaking exiles from Venezuela. At least 80,000 have settled in Florida since Hugo Chávez came to power in 1998. The Cuban vote is crucial if McCain is to counter the surge of support for Obama in south Florida.

The three counties surrounding Miami are the Democratic heartland of Florida. The Obama camp's strategy for Florida depends on beating McCain by a 600,000 vote margin to take the entire state. They hope to get a third of their supporters to take part in early voting - a goal made easier yesterday after Florida's Republican governor ordered polling stations to extend their hours following long queues.

The Obama camp also says it has won over a substantial share of younger Cubans, those who were born in this country and identify more strongly with domestic American issues.

"A lot of the people coming over from the island that have only been here about 10 years tend to vote more Democratic than Republic," said Carmen Elliott, who was a toddler when her family left Cuba in 1962.

'Top prize'

Florida is a hotly contested swing state. With 27 electoral votes, it is a top prize, and its demographic profile makes it close. The polls show Barack Obama three points ahead of John McCain. Florida's influential Cuban-American community, its military population, and "panhandle" conservative whites tend to back Republicans. But the large population of "snowbirds", retirees from the north, the state's non-Cuban Hispanics and black population are likely to back Obama. In the 2000 election, the infamous "hanging chads" - bits of paper representing ambiguous votes on paper ballots - threw the Florida poll into chaos.

· This article was amended on Saturday November 1 2008. Hugo Chávez did not come to power in 2000. He was elected in 1998 and re-elected in 2000 and 2006. This has been corrected.