Joe Lieberman has been happily screwing democrats for 8 years, did a shitty job investigating the Bush administration (0 Senate-lead investigations), and is very unpopular with democrats nationwide (he grabbed about 1% of the vote in 2004).
So why is Bill Clinton stumping for him?
There are worthier candidates than Joe Lieberman to trust with Power.
Fool me once, right?
ADDENDUM: A spokesman for Bill Clinton sez it ain't so that Bill is stumping for Lieberman. Story here.