Article I, Section 3, Clause 6:
The Senate shall have the sole Power to try all Impeachments. When sitting for that Purpose, they shall be on Oath or Affirmation. When the President of the United States is tried, the Chief Justice shall preside: And no Person shall be convicted without the Concurrence of two thirds of the Members present.
Just as the Constitution vests the House with
sole1 authority to impeach government officials,2 it entrusts the Senate with the
sole power to try impeachments.3 And just as the Constitution authorizes the House to establish its own procedures, including for impeachments, it empowers the Senate to determine its own rules for impeachment trial proceedings.4 The Senate's impeachment rules have remained largely the same since their adoption during the trial of President Andrew Johnson.5 However, while most impeachment trials were historically conducted on the Senate floor with the entire Senate participating, the Senate adopted Rule XI in 1935, which permits a committee to take evidence during impeachment trials.6 This rule was first implemented in the trial of Judge Claiborne in 1986; and the contemporary practice, at least with respect to the more common impeachment of federal judges, is for the Senate to appoint a special trial committee to receive and report evidence.7 After issuance of a report, the full Senate then convenes to consider the report; and after a closed deliberative session, publicly votes on the impeachment articles. The immediate effect of conviction upon an article of impeachment is removal from office,8 although the Senate may subsequently vote on whether the official shall be disqualified from again holding an office of public trust under the United States.9 If future disqualification from office is pursued, a simple majority vote by the Senate is required.10
Because impeachment is a political process largely unchecked by the judiciary, the role of the Senate in impeachment proceedings is primarily determined by historical practice, rather than judicial interpretation.11 Examination of the Senate's practices is thus central to understanding the Constitution's provision granting that body power to conduct impeachment trials.