Expulsion from the United States Congress
Expulsion is the most serious form of disciplinary action that can be taken against a Member of Congress. The United States Constitution () provides that "Each House [of Congress] may determine the Rules of its proceedings, punish its members for disorderly behavior, and, with the concurrence of two-thirds, expel a member." The processes for expulsion differ somewhat between the House of Representatives and the Senate. Censure, a less severe form of disciplinary action, is an official sanction of a member. It does not remove a member from office. Process leading to expulsion. Presently, the  disciplinary process begins when a resolution to expel or censure a Member is referred to the appropriate committee. In the House, this is the Committee on Ethics (House Ethics Committee); in the Senate, this is the Select Committee on Ethics (Senate Ethics Committee). The committee may then ask other Representatives or Senators to come forward with complaints about the Member under consideration or may initiate an investigation into the Member's actions. Sometimes Members may refer a resolution calling for an investigation into a particular Member or matter that may lead to the recommendation of expulsion or censure. Rule XI  (Procedures of committees and unfinished business) of the Rules of the House of Representatives states that the Committee on Standards of Official Conduct can investigate allegations that a Member violated "any law, rule, regulation, or other standard of conduct applicable to the conduct of such Member ... in the performance of his duties or the discharge of his responsibilities". The Senate Select Committee on Ethics has the same jurisdiction. The committee may then report back to their whole chamber as to its findings and recommendations for further actions. When an investigation is launched by either committee, an investigatory subcommittee will be  formed. Once the investigatory subcommittee has collected evidence, talked to witnesses, and held an adjudicatory hearing, it will vote on whether the Member is found to have committed the specific actions and then will vote on recommendations. If expulsion is the recommendation then the subcommittee's report will be referred to the full House of Representatives or Senate where Members may vote to accept, reject, or alter the report's recommendation. Voting to expel requires the concurrence of two-thirds of the members. This is set out in Article 1, Section 5, Clause 2 of the United States Constitution. Expulsions  from Congress. In the entire history of the United States Congress, 20 Members have been expelled: 15 from the Senate and five from the House of Representatives. Seventeen of these 20 were expelled for supporting the Confederate rebellion in 1861 and 1862. One member's expulsion, Senator William K. Sebastian of Arkansas, was posthumously reversed. Censure has been a much more common form of disciplinary action in Congress over the years, as it requires a much lower threshold of votes to impose. Other initiations of actions to expel. There have been numerous other attempts to expel members of Congress. In  many of those instances members under serious threat of expulsion resigned, including: There were other instances in which investigations were brought, but the defendants were exonerated, expulsion was rejected, insufficient evidence was found, or the member's term expired: