IF NADER RUNS, I think he'll pick up a fair number of former Dean supporters. Here's some evidence in support of that proposition.
UPDATE: Reader Don Byrd emails that these quotes are unrepresentative:
I've met probably 500 Dean supporters one time or another during the last year in Nashville, and I can count on one hand the number of them who say they voted for Nader. At a meetup (attended by about 150 Dean supporters) I hosted in September, I introduced one of those guys, thinking he could speak to the job we're doing trying to entice greens into our efforts...but to my shock (and missing the point) he was roundly booed by the crowd when I introduced him as a Nader voter. Dean supporters are anti-Bush Democrats, but Democrats nonetheless.