By Laura Trevelyan
BBC News, New York
Being mayor of the town that likes to style itself the capital of the world is a high-profile job - which shot to even greater prominence in the aftermath of 9/11 when Rudy Giuliani led New Yorkers through their darkest hour.
Opponents paint Bloomberg as wealthy and out of touch
Two months after the twin towers collapsed, when smoke was still rising from Ground Zero, Michael Bloomberg was elected mayor of the still grieving city.
This November, he is running for re-election, in what is shaping up to be a tight race.
A billionaire financier, Mike Bloomberg is a Republican - and, says veteran New York political consultant Hank Shienkopf, "New Yorkers elect Republicans in reaction to a crisis.
"They elected Giuliani because of crime, Bloomberg after 9/11. Bloomberg's task is to persuade New Yorkers he's the man for the job even when there isn't a crisis."
Mayor Bloomberg has a good story to tell the voters of New York.
Crime is down, school results are up, and Manhattan is recovering after 9/11. Even his critics say he has lessened some of the tension on the streets which built up during Rudy Giuliani's crackdown on crime and homelessness.
But the mayor's opponents are trying to paint him as remote, wealthy, and out of touch with the concerns of ordinary New Yorkers.
Democrats are attempting to capitalise on the mayor's failure to build a new football stadium in Manhattan's Far West Side neighbourhood.
Mr Bloomberg wanted to use public money to encourage the Jets football team to site their new stadium in a little-used area of Manhattan. This, he argued, would regenerate the West Side highway and provide a stadium which could be used to host the Olympics in 2012, should New York's bid be successful.
Residents opposed plans for a stadium in West Side Manhattan
Opponents said the stadium would only benefit the Jets, not ordinary New Yorkers - and local politicians voted against it.
In the few weeks remaining before the International Olympic Committee makes its decision on which country should host the 2012 games, the mayor is pushing an alternative stadium venue in Queens.
To counter the perception that he is remote, the mayor's first ad campaign featured him speaking Spanish.
This, said political consultant Hank Sheinkopf, was significant. Not only was Mr Bloomberg targeting the growing Hispanic vote, but by appearing with children and the elderly, he looked ordinary and approachable.
The Hispanic vote will be fiercely fought over at this election.
The Democrats have not chosen their candidate yet, but the frontrunner is Fernando Ferrer, who is of Puerto Rican descent.
At the recent Puerto Rican parade through Manhattan, the mayor and Mr Ferrer were pressing the flesh, trying to build up support in one of the key voting blocs.
Fernando Ferrer is a frontrunner for the Democrat ticket
This mayoral campaign could be one of the most expensive ever in American political history.
Observers suggest Michael Bloomberg could spend up to $150m on his campaign, while Fernando Ferrer, if selected, could spend $50m.
Mr Bloomberg is not accepting state funding, which means he can spend as much of his personal fortune as he likes.
In 2001 Mr Bloomberg justified this approach saying he was an outsider who needed to spend money so New Yorkers could get to know who he was.
So who will win this expensive and tightly fought contest? As the former New York Mayor Ed Koch, a Democrat who is supporting Mr Bloomberg in this race, told me: "New York politics is a blood sport. Bloomberg should win but anything can happen."