According to the Times:

New York Mayor Michael Bloomberg on Tuesday switched his party status from Republican to unaffiliated, a stunning move certain to be seen as a prelude to an independent presidential bid that would upend the 2008 race. The billionaire former CEO, who was a lifelong Democrat before he switched to the GOP for his first mayoral run, said the change in voter registration does not mean he is running for president [Editor's note: the change in registration means he's running for president]. "Although my plans for the future haven't changed, I believe this brings my affiliation into alignment with how I have led and will continue to lead our city," he said.

Now we can argue for real over who he takes votes from. Does he get anti-war Republicans? Anti-Hillary Dems? Anti-smoking Jets executives? It also, of course, suggests that he's likely to pursue big ideas like PlaNYC with more vigor than he might if they were just about his legacy. He'll be especially politically invested in his agenda. But will New York Democrats now have added incentive to oppose that agenda, especially if it looks like he'll be a real threat to Hillary?