With all the love Lieberman is showing to the McCainiac these days, I say it's time to kick Lieberman out of the Democratic caucus.
Now I know what you might be thinking, if Lieberman caucuses with the Republicans, they become the majority in the Senate, and we don't want that - do we? I say we do.
First, the Senate can't pass anything without the House (except to approve Presidential appointments, of which none significant are pending). The House is solidly Democratic, and is staying that way, so at least no harm will come of it. Bear in mind that with the current filibuster rules (and a few edgy conservative Democrats), it is virtually impossible to get any progressive legislation passed in the Senate as it is, and those same rules will make it virtually impossible for a Republican majority to pass anything regressive.
Second, if Republicans control the Senate, and the Senate does nothing, they can't readily blame Senate Democrats. So let the Republicans have the Senate back for a few months. The Democrats are already poised to pick up at least 5-6 seats in November anyway, and in the meantime Obama and all Democratic Senate candidates will have a do-nothing Republican Senate to run against, as well as a catastrophe of an incumbent President.