He's from New York, an independent and Jewish. If New York Mayor Michael Bloomberg runs for the White House, he will face those three issues, any one of which could sink a presidential campaign, experts say.
Bloomberg fueled speculation about an independent run for president when the self-made billionaire severed ties with the Republican Party on Tuesday and became non-partisan, though he insists he has no plans to run.
New York City is more liberal and more ethnic than the United States as a whole, and though economic revival and sympathy after the September 11 attacks have softened America's view, people remain wary of the Big Apple.
"Certainly historically it has been a problem. Americans are at best ambivalent about New York," said Thomas Bender, a history professor at New York University.
"Religion may be very important in Bloomberg's case because New York represents Jewishness to a lot of people and we're still awaiting our first Jewish president," Bender said.
Or, as Bloomberg himself put it in a New York Magazine interview last year: "What chance does a five-foot-seven (1.70-metre) billionaire Jew who's divorced really have of becoming president?"
While no independent in the modern era has ever won, the 2008 campaign is loaded with potential "firsts" with a woman, a black, a Mormon and an Italian-American all doing well in the polls.
New York candidates have won, or at least white male Protestant ones. Franklin D. Roosevelt was elected four times.
Still, Bloomberg faces some of the ethnic and anti-New York bias that undermined Al Smith 80 years ago when the Democratic nominee was trounced by Republican Herbert Hoover.
Smith was an accomplished former mayor of New York City and governor of New York state, but he was an Irish Catholic with a strong accent who looked and sounded unlike mainstream America.
Overcoming stereotypes no easy task
"Al Smith was in many ways the greatest governor New York ever had. When however the country got a look at him, he played into the stereotype of the Irish," said Pulitzer Prize-winning biographer Robert Caro.
"The Jewish issue still exists. But in addition to being a Jewish or Catholic issue, it's a New York issue. There's a certain wariness that the rest of the country has about New York."
Caro said he was optimistic Bloomberg could overcome any anti-Jewish bias. "It's a formidable stereotype but not an insurmountable one."
He noted that while voters were mistrustful of a Catholic in 1928, they elected John F. Kennedy in 1960 when Kennedy actively confronted the issue during the campaign. Irish- and Italian-Americans no longer face the prejudice of the past.
One leading New York candidate in the race, Democratic Sen. Hillary Clinton, has only lived in the state since 2000. Another, former New York Mayor Rudy Giuliani who is a leading candidate on the Republican side, proved that gruff New Yorkers could win over America with his performance on September 11.
"If Giuliani reverts to his 'nasty man' persona, it might revive latent anti-New York antagonisms," said Mike Wallace, chairman of the Gotham Center for New York City History.
"New York's lessened political clout seems more rooted in the capture of the Republican Party by its right-wing and sunbelt-based faction, which dragged the national political center of gravity to the right," Wallace said. "A New York candidate who could carry his or her state while mobilizing moderate Republicans might well become a serious contender."