Sen. John McCain won a breakthrough triumph in the Florida Republican primary Tuesday, and before the night was out, rival Rudy Giuliani prepared to quit the race and endorse the Arizona senator.

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"Our victory might not have reached landslide proportions, but it is sweet nonetheless," McCain said. "Tonight, my friends, we celebrate. Tomorrow it's back to work. We have a ways to go, but we are getting close."

"It shows one thing: I'm the conservative leader who can unite the party," the Arizona senator said in a brief interview with AP. "It's a very significant boost, but I think we've got a tough week ahead and a lot of states to come."

Former Massachusetts Gov. Mitt Romney came in second. Giuliani was third, and former Arkansas Gov. Mike Huckabee placed fourth. Romney and Huckabee vowed to fight on.

Asked directly if he was dropping out of the race, Giuliani said only: "I'm going to California."

Republican presidential candidates are scheduled to debate in Simi Valley Wednesday night.

"The responsibility of leadership doesn't end with a single campaign, it goes on and you continue to fight for it," Giuliani said Tuesday night, as supporters with tight smiles crowded behind him. "We ran a campaign that was uplifting."

Tuesday's result was a remarkable collapse for Giuliani. Last year, he occupied the top of national polls and seemed destined to turn conventional wisdom on end by running as a moderate Republican who supported abortion rights, gay rights and gun control.

The results seriously decimated Giuliani's unconventional strategy, which relied heavily on Florida to launch him into the coast-to-coast Feb. 5 nominating contests.

He largely bypassed the early voting states, figuring that the early states would produce multiple winners and no front-runner.

But Florida proved to be less than hospitable. The state's top two Republicans -- Sen. Mel Martinez and Gov. Charlie Crist -- endorsed McCain. And Giuliani, who once led in state polls, saw his support swiftly erode.

Clinton Wins Democratic Race; No Delegates Counted

While the Republicans fought for Florida's 57 delegates, Hillary Clinton won a Democratic event that drew no campaigning by any of her rivals and awarded no delegates.

Last year, the national party stripped Florida of its 185 delegates after it moved its primary ahead of Feb. 5.

The Democratic National Committee's move may be reversed at its party convention later this year in Denver. Clinton is engaged in an effort to try and get the delegates seated.

"I could not come here in person to ask you for your votes, but I am here to thank you for your votes today," she said. "This has been a record turnout because Floridians wanted their voices to be heard. I promise you I will do everything I can to make sure not only are Florida's Democratic delegates seated but Florida is in the winning column for the Democrats in 2008."

Obama said he would abide by the party's agreement.

"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."

Michigan also violated party rules by moving its primary to Jan. 15, and party leaders voted to strip the state of its 156 delegates as punishment.

Exit Polling Detailed

According to preliminary data from exit polls conducted for The Associated Press and television networks in the Florida presidential primary Tuesday.

Florida Republicans split based on ideology, with McCain winning 4 in 10 moderates and Romney winning 4 in 10 conservatives. McCain won among independents but couldn't beat Romney among Republicans.

About one in five Republicans cited illegal immigration as the biggest problem facing the country, and they voted strongly for Romney. The mostly non-Hispanic, white electorate favored deporting illegal immigrants to their country of origin by a 4-to-10 margin. McCain, who co-sponsored a failed bipartisan immigration bill that was criticized by many Republicans as too lenient, was supported by half of Hispanic voters.

Republicans divided on the abortion issue, with 6 in 10 anti-abortion Republicans supporting Romney and Huckabee, and about the same proportion of abortion-rights Republicans supporting McCain and Giuliani.

About one-third of Republicans in Florida said they had negative feelings about the Bush administration, including almost 1 in 10 who said they were angry at Bush. McCain won among Republicans who look negatively at the Bush years, and Romney wins among the majority of Republicans who look fondly upon the Bush administration.

Given four choices, nearly half of Florida Republican primary voters said the economy is the most important issue facing the country. Terrorism, Iraq and immigration each were picked by fewer than two in 10. McCain and Romney split the votes of Republican voters most concerned about the economy, with each getting more than one-third of their support.

Senior citizens were the largest age group voting in the Republican primary, and they supported McCain over Romney by almost a 10-point margin. McCain is 71, and his 95-year-old mother has joined him on the campaign trail.