In post 9/11 America, seeing Rudy Giuliani in the flesh can feel like meeting a living saint. That day in early September 2001 is sacrosanct in the national psyche and Giuliani is the holy symbol of American resilience; American defiance; American courage.
As the tall, angular Giuliani walks on to a stage in front of a business crowd in Miami Beach it is impossible not to think back to the fall of the World Trade Center. As he waves at the thousand-strong audience, every person is thinking of its famous totems: the falling towers, the billowing debris cloud and the mayor who refused to be defeated.
Not that Giuliani lets his audience forget. He is in Miami to lecture real-estate executives on the principles of leadership. But, inevitably, the events of 9/11 creep regularly into his talk.
He tells anecdote after anecdote, reminding the audience that while they watched the horrific events unfold on television, he was there.
"I just started making decisions," he says of the moment he heard the planes had struck.
The steps he took that day have passed into American folklore. Giuliani walked right into the heart of a stricken nation and became America's mayor. He is still on that path.
Now the march he began in the ashes of 9/11 might lead him to the White House.
He is touring the country, raising money and hiring staff. He tops the polls for the Republican primary, edging out the early frontrunner, Senator John McCain.
When faced with possible Democratic opponents, especially Hillary Clinton, he trounces them. The numbers speak a simple fact: Rudy Giuliani could become the most powerful man in the world.
But at the same time Giuliani faces challenges unique among the presidential candidates. In an age of religious conservatism, will the Republicans really choose a man who is pro-choice on abortion and pro-gay rights?
Will the evangelical Christians who supported George Bush support Giuliani?
It is not just a question for conservatives. A Giuliani run for the White House will be a candidacy like no other American politics has seen.
Giuliani's private life - three-times divorced and plagued by scandal - makes Bill Clinton's chequered past look almost virginal.
Giuliani is a man whose father was an enforcer for organised crime. A man who separated from his first wife when he discovered she was his second cousin. And there's more: scandals, rages and grudges galore. It's going to be a wild ride.
In down-at-heel Wilmington, Delaware, long lines of the great and the good from the Delaware Republican party file into an enormous, ornate ballroom. Beneath carved marble statues and classical murals, they eat fine food, drink good wine and listen to Giuliani make his pitch.
Giuliani looks every inch the presidential campaigner. He confidently lays out an optimistic vision of America in an accent tinged by his flat, native Brooklyn vowels.
His talk is punctuated by applause and finishes with a rousing standing ovation as he is presented with an award for his services to the cause of freedom. Then he is mobbed for autographs. He has won some key backers.
"I have met a lot of people in public life, but I have never met anyone who ranks higher in terms of someone who has given so much back," says Delaware Republican Congressman Mike Castle. This is a feeling gaining momentum in the Republican political classes as Giuliani crisscrosses the country building up a formidable organisation.
Since he left office as Mayor of New York at the end of 2001 he has visited 46 states and campaigned for 170 Republican candidates. He has held his first fundraiser, a swanky US$2100 ($3000)-a-head Manhattan cocktail party that netted upwards of $500,000.
He has also aggressively courted key officials close to the White House: his campaign manager will be political legend Mike DuHaime, political director of the Republican National Committee. He has also signed up Chris Henick, deputy to Bush's political guru Karl Rove.
Giuliani's campaign is now seen as such a threat to the main players - such as McCain or former Massachusetts Governor Mitt Romney - that he has already been the victim of dirty tricks. In January this year a dossier turned up in the pages of the New York Daily News detailing Giuliani's campaign strategy. It laid out fundraising targets, schedules and budgets for a massive effort.
The document also speculated openly that Giuliani's personal life and views on social issues could force him to drop out. "All will come out - in worst light," it warned darkly.
But the leak backfired. What the documents showed was the sheer scale of Giuliani's vision. It outlined plans to spend more than $21 million before the end of 2007 and to raise $100 million for the Republican nomination campaign. The plans spelt out not just how risky Giuliani's campaign could be, but also how ambitious.
"The whole race is wide open this time. It is a crowd. You can do well there if you are Rudy Giuliani," said Lee Miringoff, director of the Marist Institute for Public Opinion.
As Giuliani begins to put those plans into action, one name pops up again and again: Ronald Reagan.
Giuliani heaps praise upon America's sunny 80s president. He aims for the same political turf: balancing a tough line on national security with a cheerful outlook on America's prospects.
At a time when American TV screens fill each night with images of carnage from Iraq, Giuliani stands out with his message of optimism. In Delaware, it was a theme he returned to again and again as he honed what will become his stump speech.
"Reagan understood the power of optimistic leadership," he says. "We have to be the party of optimism, we have to be the party that looks to the future." It's a strangely positive message from a man whose career was forged in disaster and mass murder.
It is impossible to underestimate the power of Giuliani's actions in the days immediately after 9/11. He took snap decisions and organised New York's emergency response. He toured hospitals, took to the airwaves, and in the first 16 hours alone paid four visits to Ground Zero's still burning ruins.
He even identified the body of a close friend, sparing the dead man's pregnant wife the trauma. Such personal touches propelled Giuliani into the nation's psyche. But what people really remember is how Giuliani was there, while Bush was not. The President's frozen face in a Florida school room and subsequent escape to Nebraska aboard Air Force One contrasted strongly with Giuliani's hands-on heroics.
"Giuliani stepped into a void that day. Americans know that," says Paul Moses, a journalism professor at Brooklyn College who has spent many years reporting on Giuliani's career.
Giuliani became the man Americans trust. He - not Bush - was Time's 2001 Man of the Year. America was desperate for a hero and Giuliani provided it.
He has been riding that wave ever since. When he left office he toured the world giving speeches about his experience. Hiring him can cost US$100,000 a time.
"The 9/11 aura has been something that he has exploited ruthlessly," says Robert Polner, editor of the book America's Mayor: The Hidden History of Rudy Giuliani's New York.
It surrounds him still. In Miami Beach his audience eagerly packs a conference hall to listen, rapt, while their hero delivers management-speak that would make David Brent blush.
"When you are a leader you are the captain of a ship," he enthuses.
"The captain of the ship has to set a destination. If he doesn't set a destination it ends up where the currents take it. Or the wind takes it. It could end up destroyed."
Many in the audience nod sagely, taking notes. But when the speech is over and Giuliani asks for questions it is not advice on business this audience craves. Or leadership. Or even more 9/11 anecdotes. This audience wants to know what Giuliani would do about Iraq. Middle America is still looking to Giuliani to guide them through troubled times. They want Giuliani to have the answers.
He takes a measured, optimistic approach. Democrats and Republicans, he says, should get behind the aim of victory, no matter the previous mistakes. "There is no point in rooting for defeat. More important than what it means for George Bush is what it means for America if we lose in Iraq.
"Democrats and Republicans have much to disagree about, but we don't disagree about terrorism," he says.
It sounds like a stump speech again. And, in a divided country, it also sounds like a potentially powerful call to the middle ground.
Rudolph William Louis Giuliani III has always been tough. He was born to a working-class Italian-American family in Brooklyn on 28 May 1944.
His father, Harold, and his mother, Helen, were the children of immigrants. The extended family was a strange mix. On the one hand were cops, firefighters and the military. On the other was a Mob-linked uncle.
Giuliani's father fell on the rogue side of the family fence. He served time in Sing Sing jail for robbing a milkman at gunpoint and then worked as an enforcer for his brother-in-law's loan sharking operation.
But Harold made sure his son - and only child - grew up right. He moved the family away from Brooklyn to the suburbs of Long Island.
Rudy went to New York University to study law and embarked on a hugely successful career. He was one of the toughest prosecutors in the country, the man who helped destroy the Mob and tackled the most corrupt billionaires on Wall Street.
He led the charge against the Mafia in a prosecution dubbed "the case of cases", which targeted the heads of New York's five Mob families.
It worked. In 1987, eight top-level New York Mafiosi were sentenced to hundreds of years in prison. Before the case began, Giuliani had vowed: "Our approach is to wipe out the Five Families." The Mafia in New York is a shadow of what it once was.
New Yorkers have always loved a tough crime-fighter. Giuliani lost his first race for mayor to David Dinkins in 1989 but swept to power in 1993. He inherited a racially torn New York that was a by-word for crime, urban blight and a breakdown of social order.
Giuliani changed all that. He launched a radical overhaul of policing, dubbed "zero tolerance". It emphasised cleaning up small crimes - broken windows, graffiti - in the belief this would deter bigger crimes.
Coupled with more police officers and a sophisticated new computer system, it worked spectacularly.
New York is now one of the safest large cities in the world. Former slum areas such as Soho and the East Village are home to some of the most sought-after property in the world. He ran the sex clubs out of Times Square, and now it is home to MTV.
Giuliani even turned the highly Democratic city into a Republican stronghold (though only when it comes to electing its mayors).
But there is undoubtedly a darker side to Giuliani. A closer examination reveals a more troubling picture than simply an old-fashioned hero. While some might dream of crowning him the new Ronald Reagan, others see a different potential fate. "There is actually a lot about him that makes you wonder if there isn't a Richard Nixon-like quality about him," says Paul Moses.
Many who have studied Giuliani say he is authoritarian, nepotistic and capable of questionable decisions. His past mistakes could loom over him as much as his heroics.
Certainly he has not always been an inclusive figure. As mayor, Giuliani paid little attention to New York's minority groups. In two notorious cases where cops shot unarmed black men, Giuliani came out blazing in favour of the men in uniform.
Giuliani has also been controversial for his habit of promoting his friends. Being given a job by Giuliani has been likened to becoming a "made man" in the Mob.
"With Giuliani the personal is the political and vice versa," says Robert Polner. "He took patronage to whole new levels."
Bernie Kerik was a classic Giuliani appointment. He had served as Giuliani's bodyguard and driver, but his lack of a college degree should have prevented him rising to high office in the police department. But Giuliani bypassed the rules and appointed him police commissioner.
Later, he advised George Bush that Kerik would make a good head of the Department of Homeland Security. Bush took the advice and then watched Kerik's appointment process collapse in a spectacular mess of scandals ranging from immigration problems to financial irregularities to ties to organised crime.
The fear is that such mistakes will crop up again in the course of a presidential campaign. Or, worse yet, happen in the Oval Office.
"I knew a lot of people who worked with him who were afraid of him," says Polner. "He is volatile. He lashes out."
But perhaps the biggest doubts over Giuliani loom over his personal life. It has been a high-profile roller coaster. He is now married to his third wife, Judith Nathan.
His first marriage, to Regina Peruggi, was annulled after 14 years when the pair found out that they were second cousins. His second, to television personality Donna Hanover, ended in a bitter divorce fought out in the glare of New York's tabloids.
But the real fallout lay in a subplot. As the separation wound its way through the legal system, Giuliani stayed in the spare bedroom of close friend Howard Koeppel and his partner Mark Hsiao. Living with a gay couple does not go down well with many Republican activists, especially as the primary process is dominated by evangelical Christian voters.
"Giuliani's electability in a general election greatly exceeds his electability in the primary season," says Larry Haas, a political commentator and former official in the Clinton White House.
The fact is, Giuliani represents a forgotten socially liberal Republicanism. He is pro-gay rights and pro-gun control. Most importantly he is pro-choice on abortion, the great litmus test for American evangelicals. Many pundits cannot imagine Giuliani overcoming natural conservatives such as the Mormon Mitt Romney and Kansas Senator Sam Brownback. Even McCain, whom many evangelicals despise, is reliably anti-abortion.
But that analysis may be too simple. In Delaware Giuliani is asked for the umpteenth time if his views on "social issues" would be fatal to his presidential ambitions.
"I don't get to decide what the issues are. But they are not usually the ones you think they are going to be," he says.
He is right. National security will still be the overwhelming issue of 2008.
Giuliani's strong credentials there could make up for weaknesses elsewhere.