Roger Simon at Politico seems to think it’s a possibility:
While today it looks impossible that anyone would challenge Obama, in politics you have to prepare for the impossible. Russ Feingold, the Wisconsin senator who lost his reelection bid Tuesday, has been mentioned but denies interest. Michael Bloomberg’s name is sure to come up, but the New York mayor has no real base outside the New York press corps.
Dean is different. He has run for president before — albeit briefly — which is not essential but can be very helpful. He is still a hero to many young people for his pioneering use of the Internet as a political tool. Most important, he appeals to liberals for his dramatic challenge to Democrats to stop being wimps and rolling over for George W. Bush. In 2003, Dean said he represented “the Democratic wing of the Democratic Party,” a call that might sound appealing now to liberals who fear Obama will compromise even further with Republicans. And Dean, a doctor, was a champion of the health care public option, which Obama abandoned.
But the big issue is compromise. Obama actually wants to get things done. Which means he has to compromise with Republicans and has to risk angering and losing his liberal base. That makes him vulnerable to attack from the left, which is where Dean now stands.
Dean has a lot more credibility than he had in 2004. He knows the party machinery well since he subsequently headed the DNC, and even gained some cred among Republicans for exhibiting some independence his harsh criticisms of the health care bill. While the Politico piece hangs mostly on pure speculation, I’ve certainly seen crazier ideas come to fruition.