For all of his billions, Mayor Michael Bloomberg lacks one thing all the current presidential candidates proudly display: a spouse.
The country has not elected a bachelor president since 1884, when Grover Cleveland won the White House despite newspapers huffing that "a man who will not marry a woman and take care of her has no right to be a president."
Singles haven't had much luck getting nominated either. The last unwed candidate chosen by a major party was Adlai Stevenson, the divorced Democrat who lost to Republican Dwight Eisenhower twice in the 1950s.
Bloomberg, 65, has a companion of seven years, Diana Taylor, and essentially lives with her. Their arrangement and his star-studded past love life would present him with new political territory to navigate if he runs.
In a race where spouses are playing a visible role - and one happens to be a former president - it's hard to guess how the nation would react to a bachelor candidate, says Anthony Eksterowicz, a James Madison University political science professor who is teaching a seminar on first ladies.
"It's a great unknown - we haven't had a lot of this so it's very difficult to say how the American public will accept it," said Eksterowicz, who wrote "The Presidential Companion: Readings on the First Ladies." "It would have to be managed very carefully and in a different way than if he was married."
Other bachelor candidates have drifted on and off the trail in recent years, including Bob Kerrey and Jerry Brown in 1992, Dennis Kucinich, who has since married and is running again, in 2004, and Ralph Nader, who has run several times. But seldom have they had as much attention to their romantic entanglements as Bloomberg, whose relationships over the years have been tracked in New York gossip pages.
He has been linked to singer Diana Ross, model Marisa Berenson and fashion designer Mary McFadden, to name a few.
Bloomberg and his City Hall aides are guarded about his private life; spokesman Stu Loeser declined to comment for this story. But some past partners offer a few details that give a glimpse of his single life.
His first 10 years as a Wall Street up-and-comer were spent playing and working hard. With his bachelor buddies, he boasted in his 1997 autobiography, "I set new records in burning the candle at both ends."
During that time he met fellow Harvard Business School alum, Sharon Baum, and the two were casually involved - going on dates "that by today's standards were probably not that sophisticated," Baum said in an interview.
Bloomberg has said one of his favorite dates in those days was to take a lady on a five-cent Staten Island ferry ride with a pizza and a six-pack.
"It was one of the most romantic cruises for a nickel you could get," he reminisced earlier this year.
When Baum married a few years later, he sent her a dozen roses on her wedding day.
"He isn't really any different than the way he was back then, in 1967 and 1968," Baum said. "I don't think he's changed his stripes, his integrity, and that's why I think he'd be great as a
president, bachelor or not."
In 1973, Bloomberg began dating Susan Brown. The couple wed in 1976 and had two daughters - Emma in 1979 and Georgina in 1983.
During the 1980s, Bloomberg was busy nurturing his new financial information company, which bears his name and would later earn him billions. As work consumed his time, the pair drifted apart, he wrote.
They decided to divorce in 1993 and are still close, spending some holidays together as a family.
After his divorce, Bloomberg developed a habit of asking people "Do you know anybody I could go out with?" according to a woman who dated him for several months after meeting him this way.
He is said to still use this line - now more as a joke, since he is in a relationship.
He also was known back then to consult with the food editors at his company to find out the best restaurants to take his dates.
The businessman, whose company grew out of an innovative way to use financial information, was said to have done background searches on women with whom he was fixed up. This was long before the days of Googling a blind date, and many women found it surprising but flattering.
His former flames who spoke with the AP - including one who broke up with him in a screaming fit in front of his company's headquarters - all praised him and said he was a caring partner who treated them with respect.
None would list anything they didn't like, although some were said to be hurt by his resistance to a second marriage.
He was in a serious relationship for several years with Mary Jane Salk, the widow of the child psychologist Lee Salk. So serious that he purchased a multimillion-dollar Park Avenue condo for her, which he still owns and where she still lives.
Salk told the AP that "Mike's a fabulous guy," but declined to discuss their relationship.
McFadden, the fashion designer whom Bloomberg dated briefly just before his 2001 mayoral run, said he is "diplomatic" about ending relationships. Theirs, she speculated, didn't last because she wasn't so interested in the political world he was about to join.
McFadden, like other women who spoke to the AP, enthusiastically endorsed Bloomberg, should he attempt a White House run – something he publicly denies any interest in doing.
Berenson, the actress and model, said by phone from Paris that Bloomberg is "a wonderful man and a good friend," and said "it would be great" if he ran.
There is speculation that he won't run for president without first marrying Taylor, whom he met in November 2000 when they were seated next to each other at a budget commission dinner. But Bloomberg - who is known to jokingly try and persuade newly engaged people to change their minds - may simply bet that bachelorhood won't be an issue.
The declared field of candidates already represents a hodgepodge of typical American marital situations - Republicans John McCain and Fred Thompson have both been divorced, Republican Rudy Giuliani is in his third marriage and Democrat Hillary Rodham Clinton has endured her husband's troubles with infidelity.
Bloomberg wrote in his book that the idea of a first lady is antiquated.
"The concept of 'corporate wife' or 'first spouse' really turns me off," he wrote. "No one actually needs to know the inner workings of their spouse's place of employment, nor should he or she have a ceremonial role in representing the company, or even our government."