Michael Bloomberg (I-New York)

This just in from Jay Carney, reporting from the LAX tarmac:

The Mayor of New York is officially bolting the Republican Party, and is laying the groundwork for an independent run for the White House. Current TIME Magazine coverguy Michael Bloomberg has been in Los Angeles yesterday and today, participating in a conference on post-partisan leadership with fellow TIME coverguy Arnold Schwarzenegger and LA Mayor Antonio Villaraigosa. Now it looks like he is putting post-partisanship into practice in what is potentially a very big way.

Jay's sources tell him Bloomberg is leaving the GOP not because he's suddenly realized he doesn't have a home there (fact is, he never did), but as part of his very methodical preparation to launch an independent campaign for President. The key issue here is that he has to be "unaffiliated" in order to collect the signatures to get on the ballot in various states as an independent. The billionaire Mayor has not yet decided for certain that he will run, but he's making sure that the option is there. The prospect of a self-financing candidate with Bloomberg's financial resources could serve to raise the already astronomical table stakes for everyone else in the race.