By Michael Levenson and Sasha Issenberg, Globe Staff
MIAMI -- Senator John McCain pulled out a narrow but pivotal win over Mitt Romney today in Florida's Republican primary, claiming all the state's delegates and the title of front-runner as the two-man nomination race heads toward Super Tuesday.
Rudy Giuliani, the former New York mayor who staked his presidential hopes on Florida, finished a distant, disheartening third and strongly hinted that he would withdraw, as soon as today. Former Arkansas Governor Mike Huckabee was fourth, but plans to stay in the race.
In the biggest, most diverse state yet to vote, McCain edged Romney 36 percent to 32 percent, with 62 percent of precincts reporting. More tellingly for McCain, who won with the support of independents in New Hampshire and South Carolina, only registered Republicans could vote in Florida.
With Florida's 57 delegates from the winner-take-all contest, McCain took the overall lead in delegates with 93, compared to 59 for Romney and 40 for Huckabee.
Now, McCain and Romney will embark on a breakneck, coast-to-coast race to lock down as many states as possible before what amounts to a national primary next Tuesday, with 21 states holding Republican contests. Many of them, including delegate-rich states such as New York, are winner-take-all, meaning that a candidate could rapidly pile up delegates.
McCain fared better among self-described moderates and liberals, among veterans, among older voters, and among Hispanics, while Romney beat him among conservatives, those who supported President Bush, younger voters, and white voters, according to exit polling conducted for the Associated Press and the TV networks.
McCain won among those voters who favored a candidate who says what he believes, and among those who favored a candidate with the right experience. Fewer than 1 in 5 Republicans cited illegal immigration as the biggest problem facing the country, a group that voted strongly for Romney.
McCain's victory capped an acrimonious and intense week of campaigning in which both candidates fought to set the agenda. McCain, a decorated Vietnam veteran, sought to keep the focus on Iraq and Islamic extremism, calling them the most pressing issues facing the country. But as the financial markets tumbled, Romney, a former venture capitalist, tried to put the focus on the economy and the housing crisis and criticized McCain as a creature of Washington unfit to handle an economic downturn.
Romneyís message -- that he could turn around the economy like he turned around businesses, the 2002 Winter Olympics, and the state of Massachusetts -- seemed to resonate with some voters.
"Itís just so impressive," said Judith Huffer, the editor of a church newsletter in Homosassa, who heard Romney speak at a company that manufactures flight simulators. "No matter what situation he gets into, itís just like -- boom -- he makes it all better."
But McCain narrowly won among voters most concerned about the economy, according to the exit polling.
McCain also enjoyed support from Governor Charlie Crist and Senator Mel Martinez, prominent Florida Republicans who endorsed his candidacy in the final days and then campaigned by his side. McCain was also endorsed by other influential Cuban-American politicians.
Romney, by contrast, was backed by lower-profile politicians. Today, as McCain made a final push for votes with Crist at his elbow, Romney was introduced at a sparsely attended rally by Anthony Trey Traviesa, a state representative from the Tampa area.
The final 48 hours of the campaign was marked by a bitter exchange of charges. Romney attacked McCain for bucking Republican orthodoxy and joining with prominent Democrats to push energy legislation, campaign finance restrictions, and comprehensive immigration reform. McCain accused Romney of having proposed a date to withdraw troops from Iraq. Both men labeled the other a liberal, underscoring the heated competition for conservative Republican voters, and both unleashed barrages of automated, negative phone calls.