ORLANDO, Fla. - John McCain won the Florida primary yesterday, establishing himself as the clear front-runner for the Republican presidential nomination heading into a potentially decisive battle with Mitt Romney in the week to come.

Rudy Giuliani, the former New York mayor who had staked his campaign on the Florida outcome, finished a distant third, setting the stage for his expected withdrawal.

Giuliani will endorse McCain today in California, Republican officials told the Associated Press last night, speaking on condition of anonymity. A Republican presidential debate is scheduled in California tonight.

McCain's winner-take-all victory in Florida was significant for him because it came in a closed primary in which political independents - his margin of victory over Romney in New Hampshire and South Carolina - were not permitted to vote.

With McCain ahead in national polls and leading in many of the larger states that vote on Super Tuesday next week, his campaign now may be difficult to stop.

"My friends, in one week we will have as close to a national primary as we've ever had in this country," the Arizona senator told supporters in Miami. "I intend to win it and be the nominee of our party. . . . We have a ways to go, but we are getting close."

On the Democratic side, Sen. Hillary Rodham Clinton of New York was the winner in a contest in which no delegates were at stake and no candidates campaigned - a result of punishment imposed on Florida by the national party for holding its primary earlier than party rules allowed.

Romney, in conceding defeat to McCain last night, repeated many of his familiar campaign themes. His focus in the days ahead will be to persuade conservative voters that he is their only viable option and is the true agent of change in the race.

"Washington is fundamentally broken," Romney said at his election-night party in St. Petersburg, "and we're not going to change Washington by sending the same people back just to sit in different chairs." He said the country needed a president who "has actually had a job in the real economy."

The conventional wisdom had been that McCain might suffer in Florida, and Romney might gain, as the economy became the central focus of political conversation. But according to exit polls, McCain, who has built his candidacy around national security, managed to win the voters who saw the economy as the main issue.

McCain still has a problem with the right wing of the Republican Party, as he has for years; he lost self-described conservatives to Romney yesterday by 10 percentage points, exit polls showed. With that in mind, McCain made a point last night of describing himself as a proud "Reagan conservative."

Although the outcome figures to help McCain raise money, Romney is likely to have the financial advantage heading toward Tuesday, stemming from his personal wealth. Through Sept. 30, Romney had spent $17 million of his own on the campaign. Later this week, he must report how much more he spent through Dec. 31.

The battle between the two men, which turned nasty in the last several days, resumes tonight, when they will be joined by whomever is left in the Republican field for a televised debate at the Ronald Reagan Presidential Library in Simi Valley.

On Tuesday, 21 states hold Republican primaries or caucuses, including California, New York, Illinois, New Jersey, Georgia and Missouri.

Many of the Super Tuesday states are winner-take-all on the Republican side, which gives McCain the opportunity to open up a big, perhaps insurmountable lead in the delegate count and offers Romney the chance to rally.

For Giuliani, the Florida results marked the culmination of a dizzying fall from the political heights.

The man who led New York City through the aftermath of Sept. 11, 2001, was the front-runner in the national polls for nearly all of 2007 and once seemed well-positioned in some early-primary states.

But he never seemed to figure out precisely how or where he wanted to run. Regarding New Hampshire, for instance, he vacillated between being "one-half and three-quarters committed" to the state, in the words of a party official there.

Finally, after making halfhearted efforts in some states and no effort in others, Giuliani decided to bet it all on Florida. He campaigned here nonstop for three weeks, having the state to himself for much of that time.

And the more he campaigned, the more his poll numbers dropped, a phenomenon that had occurred in other states.

"You don't always win, but you can try to do it right," he told supporters in Orlando last night. Asked directly if he was dropping out of the race, Giuliani said only: "I'm going to California," the AP reported.

Assuming Giuliani is finished, he will have established a new standard for futility in the annals of Republican-nomination politics.

In 1980, John B. Connally of Texas spent $11 million to win one delegate. This year, Giuliani spent roughly $60 million for one delegate, won in Nevada.

Besides the death watch for the Giuliani campaign, the final days in Florida featured escalating and increasingly personal exchanges between Romney and McCain.

Romney accused McCain of wanting to set "a liberal Democratic course" for the nation, reminded Republicans that Democrat John Kerry had toyed with having McCain as his running mate in 2004, and repeatedly referred to McCain's past comments that economics was not his strongest suit.

McCain accused Romney of supporting last April the idea of setting a secret timetable for U.S. withdrawal from Iraq and noted that the former Massachusetts governor had taken several different positions over the years on various issues.

Former Arkansas Gov. Mike Huckabee all but abandoned Florida in the end, spending time in the Super Tuesday states of Alabama and Tennessee. He finished fourth yesterday. Texas Rep. Ron Paul, who ran last, did not campaign in the state.

As for the Democrats, Clinton came to Davie, Fla., last night to claim victory in what was, at least for now, just a beauty contest.

"I am thrilled to have this vote of confidence you have given me today," she said, promising to help the state get back all its 210 delegates.

On the delegate front, Florida could be a battleground again later in the nominating process. If Clinton or Sen. Barack Obama of Illinois clinches the nomination early, the delegates are likely to be restored with little controversy.

But if the race goes all the way to the summer convention, the fate of the delegations from Florida and Michigan - which is in a similar situation - could make a huge difference.

On the Republican side, Florida also will be looking to undo the 50 percent penalty it received for its too-early primary. As of now, the state has 57 Republican delegates, half its original allocation.

Primary Results

Here are the vote percentages each candidate won in Florida yesterday. Winners are shown in bold.

Republican - 57 delegates*

*The GOP stripped Florida of half its 114 delegates as punishment for moving up its primary in violation of party rules.

Candidate % of Vote

John McCain 36

Mitt Romney 31

Rudy Giuliani 14.7

Mike Huckabee 13.5

Ron Paul 3.2

95% of returns counted

Democratic - 0 delegates**

**The Democratic Party stripped Florida of its 210 delegates as punishment for moving up its primary in violation of party rules.

Candidate % of Vote

Hillary Clinton 49.5

Barack Obama 32.9

John Edwards 14.4

95% of returns counted

EndText

Get the latest results, the primary schedule, delegate count and more at http://go.philly.com/campaign2008EndText

Contact senior writer Larry Eichel at 215-854-2415 or leichel@phillynews.com.