Greenfield is a former member of the pathetic US Green party. The "former" part of that characterization initially sounds good; but unfortunately, he only left the party last month, so that he could enter the Democratic primary. In other words, he doesn't seem to have minded the Greens' feeble lie-down-and-die strategy of supporting Kerry back in '04.
Indeed, there is depressingly less to this gambit than meets the eye. The press have taken an interest in it, but running in a Democratic primary is a form of self-mutilation. Greenfield may see to it that she gets some embarrassing questions on the stump, but he won't take the nomination away from her, or deprive her of a minute's sleep.
What would be more fun, and more interesting, and more constructive, would be if he ran in the general election on a third-party anti-war ticket. Even if the war is over by then, people have a healthy respect for the idea of payback -- and there's a lot of payback Hillary is due for, dating back to the way she made us all vassals of the HMOs in her husband's first presidential term. A third party determined to punish a bloody-fanged war criminal like Hillary might just deprive her of her Senate seat, and even if it missed that laudable goal, it would give all the other sellout Democrats something to worry about next time. It's like Voltaire said about Admiral Byng: "il est bon de tuer de temps en temps un amiral, pour encourager les autres" -- it's a good idea to shoot an admiral every now and then, in order to encourage the others. Voltaire, of course, was being ironical; but there's many a true word spoken in jest.