If Mayor Giuliani’s presidential campaign fizzles in Florida today, as polls suggest it will, he will face a sequence of events that will encourage him to get out of the race within hours in order to preserve his political ties and business relationships, supporters and political analysts said.

The fast-moving campaign calendar may deny Mr. Giuliani the luxury of a few days to mull over his situation. The Republican candidates are scheduled to debate at the Reagan Library in California tomorrow night and the crucial 21-state Super Tuesday battle is seven short days away. The former mayor may want to avoid the resentment he might generate by taking up time at the debate only to pull out a day or two later.

“He’s not going to want to carry on because he’s going to risk further damaging the brand,” a Republican political strategist, Scott Reed, said. “His brand name has made him a multimillionaire in a record period of time, and he doesn’t want all that to go down the drain.”

A major fund-raiser for Mr. Giuliani, Al Austin of Tampa, Fla., said he thinks the polls may understate the mayor’s strength in Florida, especially as many early-voting ballots were cast long before his slide in the surveys. He also said he thinks the mayor could benefit from a surge in negative attacks between two other Republican hopefuls, Senator McCain and Mitt Romney.

However, Mr. Austin said he expects that Mr. Giuliani will bow out gracefully if he fares poorly.

“If he got crushed, I’m sure he would make a decision right after that, rather than go on and face any embarrassment. If he is in there and competitive, then he may as well go through Super Tuesday,” Mr. Austin, a real estate developer, said.

While Mr. Giuliani could certainly bide his time for another week in hope of a change in the landscape of the race, hanging on means he would have to face New York voters. A recent USA Today/Gallup poll showed Mr. McCain leading Mr. Giuliani, 40% to 21%, in the Empire State, though an earlier Quinnipiac survey showed a dead heat.

“It is difficult to see him wanting to risk being defeated in the New York primary,” a Republican political consultant, Daniel Schnur, said. “He could ignominiously lose New York,” a professor of political science at Baruch College, Douglas Muzzio, said.

Some of Mr. Giuliani’s supporters have spoken about him pressing on if he lands in the top three in Florida. However, as he barnstormed around the state yesterday, the former mayor seemed to set a considerably higher bar. “The winner of Florida will win the nomination,” he told reporters on his campaign plane, according to the Los Angeles Times.

He quickly added that he was going to win. However, Mr. Giuliani acknowledged that his campaign schedule was up in the air after today. “When it’s Wednesday morning, we’ll make a decision,” he said, according to the Daily News. Asked about the debate tomorrow, he said, “We fully intend to participate.”

Another factor that could counsel a quick withdrawal would be a desire by the former mayor to have his endorsement carry some weight. Backers said the most likely recipient of Mr. Giuliani’s endorsement is Mr. McCain.

“If I’m going to drop out, I’m going to do it now, when I can get more credit,” Mr. Muzzio said.

The most likely perch for Mr. Giuliani in the short term is back at his consulting firm, Giuliani Partners. He could also be a logical choice for the Cabinet, especially as secretary of homeland security. Mr. Muzzio said he doubts Mr. Giuliani would consider running against Governor Spitzer in 2010 or for the mayor’s job again in 2009, which he could attempt, as the term limits law only applies to consecutive terms.

“My gut tells me we are writing the epitaph on Rudy’s political life,” the professor said. “Rudy’s never been the favorite of the Republican establishment” in New York, he added.

Analysts are divided about the wisdom of Mr. Giuliani’s decision to focus intensely on Florida, while ceding the first major Republican contests in Iowa, New Hampshire, Michigan, and South Carolina. Some view the strategy as a major mistake, as it starved his campaign of news coverage. Others view it as a logical response to an early calendar that did not play to Mr. Giuliani’s strengths.

Mr. Giuliani’s single-minded focus on national security also posed a problem as economic angst swept through the electorate, pushing terrorism fears to the back burner. However, the former mayor’s biggest problem recently was clearly the rise of Mr. McCain, who shares Mr. Giuliani’s appeal to socially moderate Republicans and independents.

“The Republicans are really having two primaries right now, a conservative primary and moderate primary. McCain and Romney are the two likely winners of those primaries,” Mr. Schnur, a former adviser to Mr. McCain, said. “Every vote Huckabee gets takes one from Romney and every vote Giuliani gets takes one from McCain.”