Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behaviour, and, with the Concurrence of two thirds, expel a Member.

Each chamber of Congress has rules of ethics and Ethics Committees to enforce them.  If convicted, usually the punishment goes no further than the public embarrassment of announcing that the member has been found to violate ethics rules.  Only two members have been expelled from Congress since the Civil War, most recently James Trafficant of Ohio in 2002.  If the violation is serious enough to warrant expulsion Congress usually either waits for voters to do the work of removing the member or more typically the member recognizes the writing on the wall and resigns.