The press has marginalized the Democrats by not resorting to their more thoughtful and cooler heads but incites the most inflammatory and defamatory statements by the most disreputable types -- including celebrities looking for some cheap publicity. In that way, they've gutted the true leadership of the Democrats and replaced them with themselves as chief spokespersons.
So they use people like Cindy Sheehan, and once they are of no use to them -- they abandon them with their delusions of grandeur to walk the streets alone. There's always the next sucker looking for a free pass to say what the press wants them to say.
It's too bad Lieberman and Miller can't take back their party from the media they've grown too dependent on to do their hard but necessary work for them. They're all but incapable of articulating any coherence anymore -- and if they do, the press won't quote them.
That's why the conservative/right/Republican blogs and discussions are so much more advanced. The mainstream media is undercutting and undermining the liberal/left/Democrats by co-opting and demanding to be their leaders -- while making the Republicans stronger by not doing them similar favors.
If one takes away the mainstream media, the real Democrats have forgotten how to speak for themselves -- because the mainstream media has taken over that function for them. But it cripples them in a world in which everyone can speak for themselves.