It's not as if any self-respecting Democrat would welcome his endorsement, so what's left for fading politician with fading influence?
Who else would want the endorsement of a deluded former Democratic nominee for VP?
As for the evidence of delusion, from the article linked above -
"I know it's unusual for a Democrat to be endorsing a Republican,'' Lieberman said at an event in New Hampshire today.
Apparently, Sen. Lieberman still thinks that he is a Democrat; that's pretty damn deluded, don't you think?