For those who have forgotten their Lieberman lore, during his original Senate racerun he was supported by none other than William F. Buckley in his against moderate Lowell Weicker. Joe's lovefests with Hannity and other wingnuts also demonstrate who Joe feels more comfortable palling around with.
If Joe feels no loyalty to the party, there's no reason to believe that he'd caucus with the Democrats and vote for them for leadership positions if he managed to get re-elected.
Lieberman 2006: The Cut-and-Run Campaign.
