Ok, so Kerry, Leiberman, and Gephardt can all go nuclear on Dean and it get's reasonable press and no one from any campaign other than Dean says anything about it. we can all agree on that, right?
so Dean in NH allegedly creates a negative flyer about Clark, and everyone goes ballistic about how it's wrong for Dean to do this to his fellow democrats.
why?
because Dean is the front runner, and everything he does is bashed no matter what it is. going negative won't help him, it will help Clark, and turn the media focus onto the meme "Why is Dean so Mean?"
by going negative, the pressure cooker his campaign is already under shows a crack or something that can be spun into a flaw, and since Clark has by and large not done any negative campaigning, makes Clark look good and Dean like a bully.
i can see going negative a few days out or right before. i can't see doing it 3 weeks out. especially with a 20 point lead in the polls.