In winning the first 2008 election restricted to registered Republicans, the Arizona senator becomes the favorite in a two-man showdown with Mitt Romney. The former Massachusetts governor's personal wealth and popularity among conservatives give him a chance to rebound next Tuesday, the biggest primary day in history.
Florida was apparently the final stop for Rudolph W. Giuliani, who led in national polls until late fall but managed to pick up only one delegate in the primaries and caucuses.
The former New York mayor sounded a note of finality in his concession speech, and there were reports last night that he would endorse McCain today.
McCain's support from Florida's two leading Republican politicians, particularly its popular governor, were crucial elements in his victory, helping to guide voters in a year in which primary contests have become a blur and voters have less time than ever to make up their minds.
There will likely be new pressure on California Gov. Arnold Schwarzenegger to abandon his neutrality and back McCain, with whom he has campaigned in the past, ahead of next week's primary in the nation's most populous state.
"Our victory might not have reached landslide proportions, but it is sweet nonetheless," McCain said last night, sounding more confident than at any time this primary season.
Looking to next Tuesday, which he called the closest thing yet to a national primary, McCain said: "I intend to win it and be the nominee of our party."
The result was a bitter disappointment for Romney, who outspent McCain by a margin of 3-to-1 and had appeared to be gaining in the final days of the campaign. But the senator fought back, accusing Romney of having wavered last spring in his support for the U.S. military effort in Iraq, a charge that Romney termed desperate and dishonest.
Romney, a former venture capitalist, stuck last night to his theme that his business background makes him better-suited for the presidency than McCain, an argument that failed to sway enough Florida Republicans during an intense, weeklong campaign throughout the state.
He will now try to overtake McCain in a coast-to-coast chase over the next week, when 22 states will hold primaries and caucuses.
It might be increasingly tough to stop him, even though Romney has a financial advantage. A late blitz of commercials by McCain enabled the senator to achieve parity on the Florida airwaves in the closing days of the race, something he'll have to depend largely on news coverage to accomplish between now and Tuesday.
McCain leads in the national polls and in many of the states that vote next week. His Florida victory should only magnify his advantage.
Tonight, the Republican candidates will meet in a final, pre-Super Tuesday debate at the Ronald Reagan Presidential Library, north of Los Angeles.
McCain "comes into California on a rocket ship," said Dan Schnur, a Republican strategist in California who worked for McCain eight years ago but is neutral this time.
"A win in Florida doesn't necessarily guarantee the nomination, but it gives him a huge advantage going into the Super Tuesday states," Schnur said. "It's going to take an awful lot of paid advertising [by Romney] to make up the difference."
Even as McCain moved closer to a prize that eluded him eight years ago, his party remains sharply divided, and many of its core voters are cool - if not hostile - to his candidacy.
Among the clear majority of Republicans who described themselves as conservatives - three in every five voters - Romney defeated McCain by a margin of 40 percent to 27 percent, according to an Election Day survey of voters as they left Florida polling places.
In his speech last night, McCain sought to reassure them, by aligning himself with Reagan and the party's conservative ideology.
McCain succeeded in countering Romney's effort to make the Florida election about managing the economy. The issue seemed to be tailored for Romney, who inundated state voters with television ads that touted his business background and argued that the country needs a president with experience in the real world, not Washington.
The exit poll found that the economy was the dominant concern yesterday, with nearly half the voters (45 percent) listing it as their top issue. Yet McCain defeated Romney by a margin of 38 percent to 32 percent among those voters.
But personal qualities, rather than issues, mattered most to McCain's voters, the exit poll found, suggesting that other factors - especially the endorsement of Florida's Republican governor, Charlie Crist, made the difference.
McCain, in spite of his reputation as a party maverick, has become the establishment candidate as the race has gone on. He got last-minute endorsements from Crist and Mel Martinez, the state's Cuban-born U.S. senator, and both men campaigned with him in the days leading up to the election.
More than two in five voters said Crist's endorsement was important to their votes, and McCain carried that group by better than a 2-to-1 margin, the exit poll showed. McCain also did well among Cuban-Americans, getting half of their votes.
McCain, 71, who would be the oldest first-term president in history, also benefited from the state's large number of seniors. He won among those 60 and older, who cast 44 percent of the total vote - the largest proportion of voters in that age group this year.
McCain also might have gotten a boost from his victory in South Carolina 10 days earlier and from fading support for Giuliani.
Pre-election polls suggested that moderates were switching from the former New York mayor to McCain as it became increasingly apparent that Giuliani was no longer a viable contender for the nomination.
Giuliani had gambled on a Florida-heavy effort, spending millions of dollars and weeks of campaign time, only to finish much closer to fourth-place Mike Huckabee, the former Arkansas governor, who had no money to air commercials. Giuliani told supporters last night that "you don't always win, but you can always try to do it right," expressing pride that he had run a positive campaign.
He picked up only one delegate in the primaries and caucuses, after spending more than $50 million -a new mark for cost-ineffectiveness in presidential politics.
That would obliterate the previous record, set by Republican candidate John B. Connally Jr., who won just one delegate in 1980 after spending $11 million, which is about $30 million in today's dollars. Because Florida's Legislature moved the date of the election ahead of Super Tuesday, the state was punished by both national parties. Republicans stripped away half of Florida's national convention delegates.
The national Democratic Party ruled that no delegates would be awarded as a result of yesterday's vote, and the presidential candidates agreed not to campaign in the state, even though their names were on the ballot.
But Hillary Rodham Clinton, expecting a first-place finish, held a Florida victory celebration anyway in an effort to gain a public-relations advantage.
"I am thrilled to have had this vote of confidence that you have given me today," the New York senator told a raucous election-night crowd in Dania, Fla., an event beamed nationwide on cable television.
However, exit poll data contained cautionary notes for Clinton's campaign. Her advantage in the nonbinding vote largely reflected ballots cast by absentee or early voters. She and Sen. Barack Obama of Illinois split the vote of those who made up their minds in the past week.
Perhaps more worrisome for Clinton, one in four Democratic voters said that Sen. Edward M. Kennedy's recent endorsement of Obama was very important to their decision, and Obama swept those voters by a margin of more than 2-to-1.
Obama - who added the endorsement yesterday of Kansas Gov. Kathleen Sibelius, the day after she delivered the Democratic response to the State of the Union - tried to play down the importance of the Florida vote.
Sen. John Kerry, the party's 2004 nominee and an Obama supporter, told reporters in a conference call that Clinton's Florida celebration was "spin to win the news cycle," adding his hope that it would "be understood for what it is."
John McCain: 93
Mitt Romney: 59
Mike Huckabee: 40
Ron Paul: 4
Rudolph W. Giuliani: 1
Needed to nominate: 1,191
Chosen thus far: 197
Yet to be chosen: 2,183
[Source: Associated Press]
* Includes pledged delegates only