Operatives for both presidential candidates are working hard to secure the only political endorsement that matters this election season: New York City Mayor Michael Bloomberg's. 

The New York Times' Michael Barbaro is reporting that Mayor Bloomberg "quietly" had breakfast with Mitt Romney Tuesday, the first meeting between the Republican nominee-to-be and the mayor. Last Friday, Bloomberg played golf with the Vice-President and the Secretary of Defense, who were no doubt pushing their own guy as the man he should throw his weight behind. 

As a right-leaning billionaire in a big liberal city — and a former member of both major political parties — Bloomberg is easily the most famous and influential "independent" in the country. Now that the primaries are over, everyone knows how members of Congress, governors, TV pundits, and newspaper editorial boards will line up. (The few people who care what they think have already made up their minds anyway.) Bloomberg, however, would be an intriguing "get" for either candidate. Not just because he's respected enough to be taken seriously on both sides of the aisle, but because we honestly have no idea which way he would go.

Bloomberg was a long-time registered Democrat, right up until the moment he decided to run for his first political office in 2001. He became a Republican for the first time on the mayor's ballot and replaced Rudolph Giuliani at the height of his power. However, being mayor of the bluest of blue cities takes its toll and in 2007 he abruptly left the Republicans and officially became an Independent, before overturning New York's term limit law and getting elected for a third time.

Why all the changing? Well, as a man who made his fortune in the financial information industry, Bloomberg obviously has an affinity for the capitalist titans who run this town. ("I have lots of friends, wealthy people, made a lot of money, were big Obama supporters, gave him money, raised money for him, who are not happy now," he said in 2010.) He's fought vicious battles with the teachers' and transit unions and silenced Occupy Wall Street on behalf of his friends. He's as 1% and you can get. However, he also shares little common ground in the cultural battles that dominate the other half of the Republican agenda. He's pro-choice, anti-gun, supports same sex-marriage, and pushed hard for some of the strictest public health provisions in the nation, like an all-out smoking ban and higher taxes on sugary sodas. Not exactly the planks of the pro-freedom platform.

On other hand, he doesn't exactly have an affinity for Barack Obama and the Democrats either. Bloomberg reportedly thinks he's "arrogant" and Obama endorsed his opponent in the 2009 mayoral election. He's defended those Wall Street friends who think they've been "vilified." They've met several times in the last year or so, but their relationship appears to be frosty at best.

In short, Bloomberg is a bit of a political oddity: A socially conscious, fiscal conservative who can actually get elected to something. (Three times!) That's what makes him such an attractive option to people like Thomas Friedman, who dream of a third-party presidential candidate. Even New Yorkers can't seems to figure out a guy who fights for more bike lanes one week, defends police spying the next, then gives an impassioned speech in defense of a mosque near the World Trade Center.

The President would probably benefit the most from a Bloomberg endorsement, since it would nicely undercut Romney's biggest selling point: his business acumen. Although, Romney would certainly enjoy tweaking East Coasters by stealing away their one conservative friend  ("See, even New Yorkers think Obama's a loser!") Even if people in the heartland, don't particularly care people what the Big City thinks. There's also the matter of Bloomberg's money, which he can both donate and raise in impressive amounts.

At this point, winning the Bloomberg endorsement is almost a defense measure. "You don't have to go out with me, just don't pick him." If he chooses not to endorse anyone, however, that might be seen as an endorsement of himself. He's already had two chances to throw his hat into the ring and declined, but his time in New York ends in 2013... Right about the time 2016 candidates start polishing their résumés