Mr. McCain scored a slim but decisive victory over former Massachusetts governor Mitt Romney. With 92 per cent of the ballots counted, the Arizona senator had won 36 per cent of the vote, five points ahead of Mr. Romney, who told supporters after the polls closed he had called Mr. McCain to congratulate him. Mr. Giuliani stood at 15 per cent.
"Our victory might not have reached landslide proportions but it is sweet nonetheless," a jubilant Mr. McCain told supporters in Miami.
Earlier, he told The Associated Press his victory shows, "I'm the conservative leader who can unite the party."
John McCain's hopes of carrying Republican colours in the U.S. presidential election were given a huge boost by his victory yesterday in the Florida primary. And he will confirm his front-runner status headed into next week's Super Tuesday if, as expected, also-ran Rudy Giuliani drops out of the race and endorses him.
In remarks to his supporters, Mr. Giuliani repeatedly referred to his campaign in the past tense and added "win or lose our work is not done. ... We'll stay involved and together we'll make sure that we do everything we can to hand our nation off to the next generation better than it was handed to us.
"The responsibility of leadership doesn't end with a single campaign," he said.
Asked about the reports that he would endorse Mr. McCain, Mr. Giuliani said only, "We're heading to California, we're heading to California."
Mr. McCain's victory gives him 57 delegates to the nominating convention in September. He, along with all candidates from both parties, will now turn his attention to next Tuesday, Feb. 5, in which 22 states hold primaries. If Mr. McCain does well in those contests, he could secure his party's nomination.
In the Democratic race, Hillary Clinton used her popularity among Hispanic voters to trounce Barack Obama. Incomplete results showed her with a 20-point margin of victory.
Exit polls showed that Mr. McCain did well among seniors, moderate Republicans and those with Cuban ancestry.
"I want to thank my dear friend, Rudy Giuliani, who invested his heart and soul in this primary, and who conducted himself with all the qualities of the exceptional American leader he truly is. Thank you, for all you have added to this race."
His victory is something of a surprise on a couple of counts. First, it showed he can do well in a state that allowed only Republicans to vote. His previous victories, in New Hampshire and South Carolina this year, and in two states in 2000, came in elections open to independents.
Also, he won the state in spite of polls that showed that voters saw the economy as the most important issue, a strong suit of Mr. Romney's, a former venture capitalist. Mr. McCain, who served in Vietnam, emphasized issues of national security.
No delegates will be awarded to Ms. Clinton, because the national Democratic Party is punishing Florida for holding an early primary. But the victory will give her a much-needed boost after losing last weekend's South Carolina primary to Mr. Obama and watching him secure the endorsement of Senator Edward Kennedy.Still, Mr. Romney was not letting go of what he clearly sees as one of his advantages in the race. "I think it's time for the politicians to leave Washington and for the citizens to take over," Mr. Romney told supporters in St. Petersburg last night.
Former Arkansas governor Mike Huckabee, who had emerged as a national figure after his surprise victory in the Iowa caucuses in early January, trailed Mr. Giuliani. But he said he wasn't discouraged by his poor showing and vowed to stay in the race. "We're playing all nine innings of this ball game," he told supporters in Creve Coeur, Mo.