I live in CT and Leiberman is my senator. He is what Democrats were when I was a child in the '50's. He is socially liberal to a reasonable degree. He likes to spend my money more than Republicans generally do. He is not crazy and doesn't make a virtue of treason. I would trust him with the country as president even if I wouldn't vote for him. It's possible to respect his point of view without agreeing with it. He doesn't make me ashamed that he is my senator the way most democrats would. Democrats like, oh say, Chris Dodd my other senator.
As long as the dems hate him/his views, the longer they will remain lost in the wilderness.