Expulsion and impeachment are both political, not criminal proceedings. I'm pretty sure you could expel a congressman for no reason at all if you have the votes, but no one would do that because of the precedent it would set.
I'm too lazy to look them up at the moment, but I know there are expulsion precedents from the Civil War era in regards to the Southerners' seats.
WyldeWolf1 The Man of 1,008 holds, making him 3 holds better than Chris Jericho!
He's fighting *for* the system of corporate money, whether he realizes it or not. No one has done more to advance corporate interests than Ralph Nader. Well, except perhaps for the Supreme Court, the other culprit in creating the Bush Administration.