Alec Baldwin sounds like he's marking his turf.
The potential candidates to replace Mayor Mick Bloomberg are at once plentiful and scarce. The front-runner, current City Council Speaker Christine Quinn, has a few strikes against her, mostly stemming from her abrasive personality and, frankly (and I speak from personal experience here) her ability to screw constituents without lubrication.
She seems to have signed a non-compete agreement with the current three-term mayor who probably dangled his (now) faltering approval ratings and potential endorsement in front of her in exchange for her almost sheep-like devotion to his agenda, which included massive cuts in assistance to the poor as well as contravening the ballot initiative that banned mayors from seeking a third term.
Apparently, Quinn wasn't paying attention all these years she's been politically active: third term mayors inevitably end up being hated. It happened with Ed Koch and the only reason term limits were passed in the first place was because Rudy Giuliani was fucking his third term up royally.
There are other potential rivals to the Speaker, notably Manhattan Borough President Scott Stringer, who is a liberal's liberal, and who has enough stroke citywide to have pondered (altho ultimately decided against) a primary challenge to Senator Kirsten Gillibrand.
Thank god, because that would have been a tough choice!
Stringer has roughly a million and a half dollars stowed away in the bank in anticipation of a mayoral run. Apart from some minor controversies (such as possibly using his influence to throw some business his parents' way) he doesn't have many skeletons in the closet and since he was raised in a power family of New York politics, he understands the map of the land better than most. And Scarlett Johansen has thrown her endorsement behind Stringer, so he's got some star power in his corner.
Baldwin tossing his hat in the ring would upset that dynamic of two liberals duking it out and offset Johansen and then some. Of course, Baldwin comes with his own weighty baggage, but he's shown he can stand in their with critics and duke it out, with intelligence, wit and just enough abrasiveness to make things interesting.