Progressives like Marcos and Randi Rhodes are missing the point and not helping Kerry in wanting to just yell at Nader.
The point is not Nader, but his supporters.
Clinton understood this, Gore did not and hopefully Kerry will.
Attacking Nader will just make him more determined and will get his supporters to rally behind him. Embracing his agenda is the best way to eliminate potential Kerry supporters from voting with Nader.
All Kerry needs to do is to continue to address the issues that Nader is raising and say he will implement them and Nader's numbers will go down (from the left at least).
In regard to Nader and why he is doing this, I do have a little insight as the person who managed the first Nader Campaign (started as a Draft campaign) in 1992.
He has no interest in being President and no interest in being in the government at all.
The theory that Rhodes advocated that Ralph will drop out and "give" his supporters to Kerry in exchange for a position in a Kerry administration shows her lack of understanding of what motivates Ralph.
In 1992, we were running a Draft movement without Nader's participation because he did not believe that elections could be used to move issues. After much pressure he agreed to come to New Hampshire, speak at some events and try to raise some issues. The crowds were huge at a time when Clinton, Kerry, Harkin, Brown and Tsongas could hardly get a handful of people to listen. By the second event, representatives of the other campaigns stood at the back of the room taking notes and within days Nader's agenda was being addressed by Brown and Clinton.
Then Nader was hooked - issues that the Democrats were ignoring were being adressed and while he was being co-opted he did not care.
The crowds got smaller as Clinton and Brown's crowds grew as they addressed the issues and positioning that Nader was using to draw crowds - the need to reform Washington with an outsider.
Clinton co-opted Nader's message and took many of his supporters by the primary election. Clinton went as far as to hire Michael Waldman who was one of the informal advisors of the Draft Nader campaign. Waldman went on to be a speech writer in the Clinton administration.
Gore and his campaign missed an easy opportunity to capture the Nader voters - he ran away from his past environmental record with the idea that he could somehow convince the "center" that even though he wrote the book on global warming he no longer believed it. He so pissed off his natural supporters that they (we) voted for Nader and he was so unbelievable to the "center" that his waffling did not get him any votes.
So far, Kerry seems to get it and his "bring it on" attitude of defending his progressive credentials and willing to advance them is brining in most of the Nader and Dean supporters. If he keeps it up, then the progressive Nader supporters will vote for him - if he shifts away from his base then they will not.
There is no talking Nader out of his run - it is up to Kerry to capture those votes. He already has got mine and much of the old Nader supporters.