Hillary Clinton and Mike Huckabee aren't the only ones chagrined at the rise of John McCain and Barack Obama. As McCain all but cemented his grip on the Republican nomination and Obama added to his Democratic primary winning streak this week, another politician's chances were also hurt: Michael Bloomberg's. The 66-year-old billionaire businessman is due to complete his second - and highly praised -- term as New York City's mayor in 2009. Prevented by term limits from running again, speculation has swirled for more than a year that he might enter the presidential race as a well-financed third-party moderate - and a trickle of reports of advisory teams and feasibility studies in the media have only strengthened the rumblings. But with the emergence of McCain and Obama, it leaves little room for a centrist independent. "If either John McCain or Barack Obama are the nominees, I think it's unlikely that Michael Bloomberg gets in. If both are the nominees, it's incredibly unlikely," said University of Wisconsin political science professor Ken Goldstein. And those hoping to see a strong Jewish contender for president in 2008 are likely in for disappointment. "What would have triggered Michael Bloomberg entering the race are divisive candidates like Hillary Clinton or Mitt Romney, who have trouble talking to the center and who came into this race with high negatives," Goldstein said. "You can't run as a change candidate if there already is a change candidate. You can't run as a maverick candidate if there already is a maverick candidate," Goldstein continued, referring to the catchphrases which are used to describe Obama and McCain respectively and highlight their appeal to independents. "It looks like there might be a change candidate and a maverick candidate [as party nominees]. It doesn't create a lot of opportunity for a third-party presidential run." Ironically, though Bloomberg has depended on there being a national yen for a moderate and potentially unifying outsider in order to have an opening, he has difficulty finding one now because the public craving for this kind of approach is so strong that both parties seem to be trying to satisfy it. New York-based Democratic political analyst Hank Sheinkopf also pointed to the personal ties Bloomberg has with the leading candidates and his desire to avoid alienating Obama and McCain. He noted that Bloomberg, a Democrat-turned-Republican-turned-Independent, has long been a strong supporter of the latter and wouldn't want to cost him votes. When it comes to the former, Bloomberg could again find himself accused of playing a spoiler, in essence, "of interfering with the election of the first African American as president of the United States, and that's not something he would want to do." (He also might not want to hurt his admittedly long-shot chances to serve as Obama's running mate.) In the past, third party candidates have been good at taking votes from the establishment candidates and less good at winning the presidency. The state-by-state winner-take-all voting process for the presidential election makes it hard for outside candidates to win; anything less than an outright majority of electors turns the process over to the House of Representatives, where congressmen would be loathe to vote for someone who doesn't belong to their party. And as the race has progressed, the window of time that Bloomberg has to enter the fray is rapidly shrinking. Just getting on the ballot as an independent in all 50 states can take Herculean efforts in organization - though with money it's possible even as state ballot deadlines begin to loom in early spring. Though the deadlines vary by jurisdiction, if Bloomberg wants to compete nationwide by almost all estimates he would have to get cracking soon after the Ohio and Texas primaries on March 4, which are likely to clarify if not seal the Democratic nomination. "As much as Michael Bloomberg is a great American and a great mayor and a great Jew, he's not going to run if he doesn't see an opportunity to win," said William Daroff, director of the United Jewish Community's Washington office and a former Republican operative who thinks the odds are too much against him now. "He's smart enough to know that running for president for the sake of running for president will not make him a more effective leader or a more effective mayor, nor will it improve his stature in the American political scene." Bloomberg, of course, is well aware of the obstacles. His own top political advisor, Kevin Sheekey, who has come up with a plan for how to mount such a presidential campaign for the mayor, outlined conditions for a run to Newsweek that suggest there's no obvious place for his boss. "You have to have opponents the country is basically unhappy with, at a time when the country is basically unhappy," he told the magazine last November for a story examining the possibility of Bloomberg running. Bloomberg himself is the first to admit he faces barriers to winning the White House, and not just of the organizational kind. When the question of running for president has come up in the past, he has quipped that a "short, Jewish, divorced billionaire" isn't very electable. Yet saying that hasn't kept him from exploring the option, as reports of market research on such a bid and meetings of high-profile figures interested in backing his candidacy have indicated. Though he has denied many times that he will be running for another office before his term as mayor is up, those who know him well have fanned the flames. Just this week, Bloomberg's head spokesman, Stu Loeser, told The New York Times that while the mayor hadn't fully thought through his next steps, he would likely find ways to continue playing a role in the civic debate. Loeser spoke to the Times as part of a story it ran suggesting that Bloomberg would be dissatisfied turning full-time to philanthropy, though it is what he has discussed doing once he leaves office. "He was extremely successful, and then he was extremely successful as mayor," major Jewish philanthropist and long-time friend Michael Steinhardt is quoted as saying. "Now where does he go from here? He doesn't really care that much about his philanthropy. I think he likes hearing himself talk publicly - terrible way to put it, but I think that's right." Bloomberg could still decide to enter the race, as improbable as Sheinkopf and other observers think it is. "He's the master of his own ship. If he wants to do it, he'll still do it," the political analyst said. Or, as Bloomberg wrote of himself in his autobiography, and Newsweek quoted in its profile, "Stubborn isn't a word I would use to describe myself; pigheaded is more appropriate . To a contrarian like me, constant advice not to do something almost always starts me quickly down the risky, unpopular path."