Look for Mayor Bloomberg’s limerence with running for president to fade away as Super Tuesday’s votes are counted tomorrow night if they show Senator McCain as the presumptive Republican nominee.

The rationale for a Bloomberg candidacy was always predicated on the expectation both parties would nominate partisan extremists — leaving moderate and independent-minded voters searching for a post-partisan alternative. The irony is that the same fuel that fired Bloomberg aspirations filtered down to voters over the last few months, providing Mr. McCain with an unanticipated surge to the front of the Republican pack and positioning Senator Obama for a real shot at the Democrats’ nomination.

The political rationale for a Bloomberg run proved prescient, given that a big chunk of the electorate is clearly motivated to break from traditional candidates. But rather than propel Mr. Bloomberg into the race, this “third way” will likely block his candidacy by influencing results in the two-party system Mr. Bloomberg disdains. Mr. Bloomberg seemed truly poised to enter the race just a couple of months ago, with Senator Clinton leading Democrats and Republicans appearing to vacillate between Mayor Giuliani, Governor Huckabee, and Governor Romney. And if the two parties do nominate Mrs. Clinton and Mr. Romney, Mr. Bloomberg could yet decide to enter the race.

Over the last few weeks, various indications have suggested Bloomberg won’t run.

Kevin Sheekey, the deputy mayor running the non-campaign, allowed several reporters to profile him. If Mr. Sheekey were on the verge of mounting (and leading) a $2 billion national campaign, he would also be on the verge of an avalanche of press attention. Mr. Sheekey is notoriously elusive — for reporters, his colleagues, even his boss — so the sudden willingness to open up and give reporters access to his thinking seemed to indicate there was a ticking timetable on how long his thinking would matter to reporters.

Back in December, a slew of local prominent business and civic leaders agreed to lend their names to a print advertisement urging Mr. Bloomberg to enter the race. This ad was so good-to-go that the New York Times prematurely reported it was about to run. The ad has yet to appear.

The chattering class suddenly stopped chattering. For a while, there was constant buzz that Mr. Bloomberg really wanted to run. Even naysayers who’d long said there was no way that would happen began acknowledging the reality that Mr. Bloomberg was serious about running. This had a particular impact in newsrooms as additional reporters were assigned to keep their eye on Mr. Bloomberg’s intentions. Those reporters have now begun to trickle back toward their usual beats.

Mr. Bloomberg’s political allies have begun to ally themselves elsewhere, most notably Governor Schwarzenegger of California, who endorsed Mr. McCain last week. That led another friend of Bloomberg / McCain supporter, Senator Lieberman of Connecticut, to speculate in The New York Sun that Mr. Bloomberg was having second thoughts. And Mr. Bloomberg’s personal money manager, Steven Rattner, is now more actively working on behalf of Mrs. Clinton, along with his wife, Maureen White.

This election marks the first time since 1928 that no sitting president or vice president even entered the race, and the first time since 1952 that no sitting president or vice president will be in the general election. A wide open race on both sides, voter fatigue with the usual presidential suspects, and a vast fortune to deploy — these were the ingredients that made Mr. Bloomberg pay real attention to running for president. That fortune is still there, and will surely fuel a round of speculation involving Mr. Bloomberg as a potential vice president. As The New York Sun reported on page one, Mr. Bloomberg could tap into his fortune on behalf of the entire ticket if he’s nominated for vice president. As Democrats chase after maximum contributions of $2,300, a McCain/Bloomberg combination could forget about fund-raising and focus on politicking.

There’s no reason to think the entrepreneur whose name adorns a global business, a midtown skyscraper and a news operation — putting aside the influence he commands as a combined mayor and billionaire — is emotionally equipped for a second-tier spot in any job. The exception that proves the rule could be the one job that is a heartbeat away from becoming the leader of the free world. Of course, this presumes Mr. McCain would want Mr. Bloomberg on the ticket. That’s not likely unless Mr. McCain wants to infuriate the conservative wing of his party.

Precisely two years after speculation about a potential Bloomberg candidacy first emerged, we do know with certainty there was real substance behind the speculation. Running for president is an idea Mr. Bloomberg ultimately embraced. But embracing an idea requires less of a commitment than attempting the impossible. And Mr. Bloomberg has no desire to run simply to lose.

goldincolumn@gmail.com