Wisconsin State Senator Tim Cullen, who left the Democratic Caucus over a hissy fit about committee assignments.

While he’s not joined the Republican caucus, which would flip the Senate.

All reports are that he was Republican Governor Scott Walker’s favorite Democrat in the Senate, so I peg this as a case of Joe Lieberman syndrome, where they act like a complete prat if they feel that they have not received the requisite obsequious adulation.