Brendan Nyhan mulls the future of Jomentum in the Democratic Party:
What happens to Joe Lieberman if the Democrats take the White House and expand their Senate majority to 56 or 57 seats? Despite his support for McCain, I think Democrats will want his vote on non-war-related issues, so they'll hold their nose and let him keep his seniority in the caucus. Others say he'll be stripped of his seniority, lose his chairmanship of the government affairs committee, and then leave the party to become a Republican.
My sympathies are with those who'd like to give Senator Lieberman the boot. Bipartisanship and heterodoxy are great, and I'm willing to tolerate even Lieberman's record of unrelenting support for the war in Iraq, but one should not be allowed to actively campaign for the Republican nominee for president and retain one's seniority within the Democratic caucus and chairmanship of a semi-important committee. That's an unequivocal signal--from Lieberman, not from Democrats--that what divides him from the party is greater than what unites him with it.
The question that needs to be asked, though, is this: Is Joe Lieberman the type of vindictive, thin-skinned individual who would be likely to cast aside his longstanding moderate-to-liberal record on most domestic issues in order to join Republican filibusters and make life miserable for Democrats in retaliation for their snubbing him? I think the answer is quite possibly yes, and that's a very good reason for biting the bullet and putting up with his shenanigans until 2012.