MIAMI - Sen. John McCain won a breakthrough triumph in the Florida primary Tuesday night, seizing the upper hand in the Republican presidential race ahead of next week's coast-to-coast contests and lining up a quick endorsement from soon-to-be dropout Rudy Giuliani.
"It shows one thing: I'm the conservative leader who can unite the party," McCain told The Associated Press after easing past former Massachusetts Gov. Mitt Romney for his first-ever triumph in a primary open only to Republicans.
"We have a ways to go, but we're getting close" to the nomination, he said later in an appearance before cheering supporters.
Sen. Hillary Rodham Clinton was the Democratic winner in a primary held in defiance of national rules that drew no campaigning and awarded no delegates.
The victory was worth 57 Republican National Convention delegates for McCain, a winner-take-all haul that catapulted him ahead of Romney in that category.
Romney, who has spent millions of dollars of his personal fortune to run for the White House, vowed to stay in the race.
"At a time like this, America needs a president in the White House who has actually had a job in the real economy," the former businessman told supporters in St. Petersburg.
Giuliani, the former New York mayor, ran third. It was his best showing of the campaign, but not nearly good enough for the one-time front-runner who decided to make his last stand in a state that is home to tens of thousands of transplanted New Yorkers. Several officials familiar with events said he intended to endorse McCain on Wednesday in California.
In remarks to supporters in Orlando, Giuliani referred to his candidacy repeatedly in the past tense - as though it were over. "We'll stay involved and together we'll make sure that we'll do everything we can to hand our nation off to the next generation better than it was before," he said.
Former Arkansas Gov. Mike Huckabee ran fourth in the primary but told supporters he would campaign on. Texas Rep. Ron Paul was fifth, and last.
Florida marked the end of one phase of the campaign, the last in a series of single-state contests that winnowed a once unwieldy field.
The race goes national next week - McCain said it would be the closest thing to a nationwide primary as any event in history. Twenty-one states hold Republican primaries and caucuses on Tuesday with 1,023 convention delegates at stake.
Returns from 81 percent of Florida's precincts showed McCain, the Arizona senator, with 36 percent of the vote and Romney, the former governor of Massachusetts, with 31 percent.
In the overall delegate race, it was McCain 93, Romney 59, Huckabee 40. Paul has four and Giuliani one.
The victory was another step in one of the most remarkable political comebacks of recent times. McCain entered the race the front-runner, then found his campaign out of funds and unraveling last summer as his stands in favor of the Iraq War and a controversial immigration bill proved unpopular.
The war gradually became less of a concern after President Bush's decision to increase troop deployments began to produce results. McCain also sought to readjust his position on immigration.
By the time of the New Hampshire primary, he had retooled his candidacy and ridden his Straight Talk Express campaign bus to over 100 town hall meetings. He won in New Hampshire, stumbled in Michigan, but won the South Carolina primary last week, taking first place in the state that had snuffed out his presidential hopes in 2000.
McCain's previous triumphs this year, and in two states in 2000, came in elections open to independents as well as Republicans. He campaigned in Florida with the support of the state's two top Republican elected officials, Gov. Charlie Crist and Sen. Mel Martinez.
Romney's only primary win so far was in Michigan, a state where he grew up and claimed a home-field advantage. He also has caucus victories to his credit in Wyoming and Nevada.
A survey of voters as they left their polling places Tuesday showed the economy was the top issue for nearly half. McCain led his rival among those voters, blunting Romney's weeklong effort to persuade Floridians that his background as a businessman made him best-suited for heading off a recession.
McCain also benefited from the support of self-described moderates, as well as older voters and Hispanics. Giuliani ran second among Latino voters, according to preliminary exit poll data.
Romney was favored by voters opposed to abortion and to easing the path to citizenship for illegal immigrants.
About 40 percent of self-described conservatives supported him, as well, compared to about 25 percent for McCain.
The poll was conducted by Edison Media Research and Mitofsky International for The Associated Press and the television networks.
The Democratic primary was controversial by its very existence, an act of defiance against national party officials who wanted it held later in the year.
Even so, Clinton sought to emphasize her performance in the state, holding a victory rally as the polls were closing.
She challenged Barack Obama to agree to seat the delegates on the basis of the night's vote, but he demurred, saying he would abide by an agreement all Democratic candidates had made months ago.
"Those decisions will be made after the nomination, not before," Obama told reporters Tuesday on a plane from Washington to Kansas. "Obviously, I care a lot about the people in Michigan and a lot about the people in Florida. And I want their votes in the general election. We'll be actively campaigning for them."