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.
ARTICLE I, SECTION 3, CLAUSE 6
The essential powers and procedures for Senate impeachment trials are set forth in this clause. The Framers vested the Senate with the „sole Power to try Impeachments” for several reasons. First, they believed Senators would be better educated, more virtuous, and more high-minded than Members of the House of Representatives and thus uniquely able to decide responsibly the most difficult of political questions. Second, the Framers vested the Senate rather than the judiciary with the authority to try impeachments because they favored, as Alexander Hamilton explained in The Federalist No. 65, a „numerous court for the trial of impeachments.” He believed such a body would be well suited to handle the procedural demands of an impeachment trial, in which it, unlike judges, should „never be tied down by such strict rules, either in the delineation of the offense by the prosecutor, or in the construction of it by judges, as in the common cases serve to limit the discretion of courts in favor of personal security.” Hamilton explained further that „[t]he awful discretion which a court of impeachments must necessarily have to doom to honor or infamy the most confidential and the most distinguished characters of the community forbids the commitment of the trust to a small number of persons.”
There are three special requirements for impeachment trials. The requirement that Senators be on Oath or Affirmation in impeachment trials was plainly designed to impress upon them the extreme seriousness of the occasion. The requirement for the Chief Justice to preside over presidential impeachment trials underscores the solemnity of the occasion and aims to avoid the possible conflict of interest of a Vice President’s presiding over the proceeding for the removal of the one official standing between him and the presidency. Moreover, the supermajority requirement was designed to facilitate serious deliberation and to make removal possible only through a consensus that cuts across factional divisions. This requirement’s impact is apparent in the fact that the Senate has convicted only seven of sixteen people impeached by the House. It was instrumental in Andrew Johnson’s trial, as the majority fell one vote short of removing him from office. In President William Jefferson Clinton’s trial, there was never a question of his removal so long as all forty-five Democrats in the Senate uniformly opposed his ouster.
In addition to the requirements in the Constitution’s text, three significant questions have arisen about Senate authority to try impeachments. The first is the minimum the Senate must do once the House impeaches someone. This question arose after the House’s first impeachment in 1797. One day after the House impeached Senator William Blount, the Senate expelled him by a vote of 25–1. Blount claimed the Senate lacked authority to try him because Senators were not impeachable and, in any event, he no longer occupied an office from which he could be removed. The Senate voted to dismiss the impeachment resolution against the expelled Blount for lack of jurisdiction. Subsequently, many Senators have construed this vote as supporting their authority to dismiss an impeachment without a full-scale trial.
The second question is the extent of the Chief Justice’s authority as presiding officer to render unilateral rulings. In the first presidential impeachment trial in 1868, Chief Justice Salmon Chase claimed the authority to decide certain procedural questions on his own, but the Senate challenged several of his rulings and overruled him at least twice. In President Clinton’s impeachment trial in 1999, Chief Justice William H. Rehnquist ruled on some procedural questions, but the Senate never challenged, much less overruled, any of these rulings.
A third question revolves around which procedures the Senate must employ in impeachment trials. Because the Constitution both provides the Senate with the „sole power to try impeachments” and empowers „Each House…to determine the Rules of its Proceedings,” the Senate has formulated its own special impeachment trial procedures (first written down by Thomas Jefferson when he was Vice President). In President Johnson’s impeachment trial, the Senate formulated an additional set of rules that have largely remained intact ever since and were followed by the Senate in President Clinton’s impeachment trial.
In 1936, the Senate amended these rules to include Rule XI, which allows the appointment of a small number of Senators to operate as a trial committee to gather evidence and take testimony. The Senate has used trial committees on only three occasions in the 1980s to assist with fact-finding regarding impeachment articles approved by the House against three federal district judges. Before the Senate and in federal court, all three judges challenged the legitimacy of trial committees. They argued the Senate’s „power to try impeachments” imposed on the full Senate the obligation to conduct a full trial. The Senate countered that it had complete authority over how to fashion proceedings and that Senators’ political accountability was the only check on this authority. Ultimately, the Supreme Court accepted the Senate’s arguments in Nixon v. United States (1993) on the principal ground that the Senate’s power to try impeachments included the nonreviewable final discretion to determine how to conduct its trials.
The Court did not address the propriety of judicial review of the Senate’s possible deviation from any explicit safeguard required by the Constitution for impeachment trials.
The Senate settled some other procedural questions raised in the 1980s, including the applicability of the Fifth Amendment Due Process Clause to and the requisite rules of evidence and burden of proof for impeachment trials. The Senate ruled that adopting a uniform rule on these questions was impractical because it lacked the means for enforcing any such rule against Senators. It decided that each question was a matter for the Senators to decide for themselves.
The Constitution fastens the responsibility of trying impeachments upon the Senate. Yet some Senators have doubted whether they have the requisite competence to try impeachments. Rule XI was adopted as a response to poor attendance and preparation by Senators in impeachment trials in the early twentieth century. Yet even in the 1980s, some Senators claimed that they had not bothered to prepare before voting, and such proceedings diverted their energies away from legislative business of greater concern to their constituents. Others argued the proceedings restored their confidence in the Senate’s institutional competence to conduct them. In any event, the Framers of the Constitution vested that task in the Senate and nowhere else.
The last question is the continuing debate over how effective impeachment is as a remedy for executive or judicial misconduct. After the acquittal of President Clinton, some commentators have wondered whether impeachment is a meaningful option for dealing with a popular President’s misconduct. Some believe that Clinton’s acquittal strengthened the presidency because it makes it less likely future Presidents will face serious impeachment attempts for private misconduct. Others think Clinton’s acquittal reflects an appropriate compromise that was consistent with the structure: he had been impeached by the House and therefore disgraced for his misconduct but not removed from office. Validation of these competing views must await future impeachment trials.https://www.heritage.org/constitution/#!/articles/1/essays/17/trial-of-impeachment