The Senate Impeachment Trial Clause

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.

—Michael J. Gerhardt

Introduction

The Constitution vests the Senate with the “sole power to try all impeachments,” and the Senate Impeachment Trial Clause provides several basic procedures for such trials. First, Senators must take an “Oath or Affirmation.” Second, the Chief Justice of the United States is the presiding officer for presidential impeachment trials, and the Vice President, as President of the Senate, presides in all other impeachment trials. Third, a two-thirds supermajority vote is required for conviction and removal from office. This requirement’s impact is apparent in the fact that the Senate has convicted only eight of the twenty-two people whom the House has impeached (all eight were federal judges). Beyond these specific procedures, the Rules of Proceedings Clause in Article I, Section 5 vests the Senate, as it does the House, with the power “to determine the Rules” for its internal governance. (See Essay No. 26.) This provision empowers the Senate to establish the procedures for impeachment proceedings.

History Before 1787

In Parliament, impeachment authority was divided between the lower and upper chambers. The House of Commons (the lower chamber) had the authority to charge, or impeach, someone for impeachable misconduct. The House of Lords (the upper chamber) had the crucial power to try impeachments and impose sanctions. It was given this authority because its members were regarded as better educated than their counterparts in the lower chamber and less prone to the passions of the moment. The upper chamber also functioned as a check against an intemperate, ill-considered impeachment rendered by the lower chamber. Each legislative chamber had the power to determine the rules for its proceedings; the lower chamber tended to delegate authority to committees for investigations of possible misconduct of public officials, and the upper chamber modeled its trials on courtroom trials. There were presiding officials and rules of basic procedures to govern the proceedings.

A similar structure was adopted in the colonies. Bribery, extortion, and misuse of funds were the most common grounds for impeachment; purely or predominately partisan impeachments often failed. This model continued following independence. For example, in Virginia, an attempt to impeach Governor Thomas Jefferson for his performance in office failed. In Pennsylvania, the lower house impeached Frances Hopkinson for abusing his authority as chief of the Admiralty Court, but the State Council, which was responsible for trying the impeachment, found that the charges brought by his political foes were largely baseless and acquitted him on all counts.

Based on this record, historians Peter Charles Hoffer and N.E.H. Hull have determined that “conviction upon trial required that the impeachment managers establish the elements of mens rea (the guilty mind), actual causation of the offense, and damage of some kind to persons or the state itself.”¹ The authors added that “the offense need not be a crime, but the elements of evil intention, causation, and actus reus [a bad act] were drawn from the criminal law.”²

The Constitutional Convention

To varying degrees, the four features of the Senate Impeachment Trial Clause were discussed during the Constitutional Convention. First, the Framers debated which body should try impeachments. Under one proposal from the Committee of Detail, the House would have the “power of impeachment” and the “Senators and Judges of the foederal Court [would] be a Court for trying Impeachments.”³ Another proposal from the Committee of Detail provided that the President could be “removed from his Office on Impeachment by the House of Representatives, and Conviction in the Supreme (National) Court.”⁴

On August 6, John Rutledge of South Carolina delivered the latter proposal to the Convention.⁵ However, on September 4, the Committee of Eleven proposed that the Senate “shall have power to try all impeachments.”⁶ The Convention postponed voting on this issue until it resolved “the mode of electing the President.”⁷ Gouverneur Morris of Pennsylvania, pointing to “[t]he difficulty of establishing a Court of Impeachments, other than the Senate,” argued that the Senate should be “the Judge of impeachments.” He continued that the U.S. Supreme Court would “try the President after the trial of the impeachment” for any criminal offenses.⁸

On September 8, the Convention returned to the issue of impeachment. James Madison of Virginia “objected to a trial of the President by the Senate, especially as he was to be impeached by the other branch of the Legislature,” and said he “prefer[red] the supreme Court for the trial of impeachments.”⁹ Morris repeated his point that “no other tribunal than the Senate could be trusted” and warned that “[t]he Supreme Court were too few in number and might be warped or corrupted.”¹⁰ Roger Sherman of Connecticut “regarded the Supreme Court as improper to try the President, because the Judges would be appointed by him.”¹¹ Madison’s proposal was defeated by a vote of nine to two with Virginia and Pennsylvania in the minority.¹²

Second, the delegates considered the oath as a possible safeguard that could ensure fair, credible impeachment trials in the Senate. On September 8, Morris proposed that “every member shall be on oath” during an impeachment trial.¹³ This motion passed by a vote of nine to two.¹⁴ The oath that Senators took upon entering office presumably applied to all of their duties as Senators, but the requirement of a second oath underscored the heightened need for impartiality and even-handedness when exercising their responsibilities in presidential impeachment trials.

Third, the delegates chose the Chief Justice to preside during the impeachment trial of the President.¹⁵ This decision would avoid the conflicts of interest that Vice President would have in presiding over the trial of the one person standing between him and the presidency. The prevailing wisdom was that no other official was likely to have the stature and commitment to the rule of law that characterized the Chief Justice, who was also immune to any direct political reprisals for any of his decisions during a presidential impeachment trial.

Fourth, the choice of a two-thirds supermajority for conviction was a significant innovation. There is not much debate or other evidence to indicate why the delegates eventually agreed to this requirement.¹⁶ It appears to have derived from a growing awareness among the delegates that a simple majority vote would have made conviction too easy. The supermajority voting requirement had the virtue of ensuring widespread agreement among the Senators in the extraordinary instance of a conviction or removal, especially one involving the Chief Executive.

Hoffer and Hull suggested that requiring two-thirds majority approval for conviction and removal “ensured that the Senate would be as thoughtful and deliberate in its hearing and determining of cases as the House of Lords, without any of the aristocratic trappings of the English body.”¹⁷ In other words, the two-thirds majority requirement ensured the rarity and difficulty of convicting and removing the Executive.

Supermajority voting requirements were not new to the delegates. For example, the constitution New York specified a two-thirds requirements for impeachments.¹⁸ The Articles of Confederation required nine of the thirteen states—a two-thirds majority—to approve treaties and other important business such as entry into war.¹⁹ The Constitution would require a two-thirds majority for a house to expel a member²⁰ or to ratify a treaty.²¹ (See Essay Nos. 27 and 106.)

The Ratification Debates

In Federalist No. 65, Alexander Hamilton defended the Senate Impeachment Trial Clause. He believed that the Senate, rather than the judiciary, should try impeachments. Rather than having a single judge or panel of judges, Hamilton favored a “numerous court for the trial of impeachments.” He believed such a large body would be well suited to the procedural demands of an impeachment trial. Unlike judges, the Senate should “never be tied down by such strict rules, either in the delineation of the offence by the prosecutors, or in the construction of it by the judges.” Hamilton explained further that “[t]he awful discretion, which a court of impeachments must necessarily have, to doom to honor or to infamy the most confidential and the most distinguished characters of the community, forbids the commitment of the trust to a small number of persons.”

During the Maryland ratifying convention, James McHenry explained that the delegates regarded the Senate as the only authority that would “more likely be governed by cool and candid investigation, than by those heats that too often inflame and influence more populous Assemblys.”²²

The Anti-Federalists opposed placing the impeachment power in the Senate. Cato, for example, warned that the Senate, being political, could not “be an impartial judicature” and would “serve as a screen to great public defaulters.”²³ Luther Martin of Maryland added that the Senate serves as “a privy council to the President,” and many influential Senators “may have advised or concurred in the very measures for which [the President] may be impeached.”²⁴ Martin also charged that Senators would be “unduly under the influence of” and dependent on the President “since they also are appointable to offices.”²⁵ In Martin’s view, the President was “constitutionally empowered to bribe his judges” through the appointment power and could nominate as Chief Justice “a person of whose voice and influence he shall consider himself secure.” In which case “there will be but little probability of the President ever being either impeached or convicted.”²⁶

Powers of the Chief Justice

In the normal course, the Senate’s presiding officer would preside at impeachment trials, and that presiding officer would be either the Vice President or another Senator chosen by the Senate. However, the Constitution requires that the Chief Justice preside over the President’s impeachment trial.

Three Presidents have been impeached. Andrew Johnson was impeached in 1868, and Chief Justice Salmon P. Chase presided over that trial. Bill Clinton was impeached in 1999, and Chief Justice William Rehnquist presided over that trial. And Donald Trump was impeached twice. The first trial, which began in 2020, was presided over by Chief Justice John Roberts. The second, which began in 2021 after Trump was no longer in office, was presided over by Senate President Pro Tempore Patrick Leahy.²⁷ Apparently, Chief Justice Roberts declined to preside over the trial of a former official.²⁸

None of these trials led to a conviction. In the Johnson trial, the majority fell one vote short of removing him from office. In the Clinton and Trump impeachment trials, there never was any doubt that both would be acquitted. There were enough members of the Presidents’ parties to ensure that, if they remained united in favor of acquittal, the Senate would not be able to meet the two-thirds threshold for conviction.

What is the extent of the Chief Justice’s powers as presiding officer? In 1868, Chief Justice Chase claimed the authority to decide procedural issues on his own, but the Senate overruled him twice.²⁹ In President Clinton’s impeachment trial, Chief Justice Rehnquist ruled on several procedural questions. For example, the Republican House managers referred to Senators as “jurors.” A Democratic Senator objected, Rehnquist ruled that “[t]he Senate is not simply a jury. It is a court in this case.”³⁰ The Senate did not challenge, much less vote to overrule, any of Rehnquist’s rulings.³¹

In 2020, Chief Justice Roberts made several substantive rulings. He reprimanded House managers and lawyers for President Trump for their language. He admonished the lawyers to “avoid speaking in a manner and using language that is not conducive to civil discourse.”³² Roberts also refused to read a question posed by a Senator that named a whistleblower.³³ Finally, he declined to break any tie vote.³⁴ With regard to procedure, Roberts closely monitored the timing of each side’s arguments. The Senate did not challenge any of his rulings.

Senate Rules for Impeachment Trials

The Senate has formulated its own special impeachment trial procedures. These procedures were first written by Thomas Jefferson when he was Vice President.³⁵ In Andrew Johnson’s impeachment trial, the Senate formulated an additional set of rules. These rules have remained largely intact and were followed by the Senate in the Clinton and Trump impeachment trials.

In 1936, the Senate added Rule XI, which allows the appointment of a small number of Senators to operate as a trial committee to gather evidence and take testimony. Rule XI was adopted as a response to poor attendance and preparation by Senators in impeachment trials in the early twentieth century.

During the 1980s, three federal district judges were impeached. For each trial, the Senate used trial committees to assist with fact-finding. Several Senators claimed that they had not prepared before earlier impeachment trials, as such proceedings diverted their energies from legislative business of greater concern to their constituents. Other Senators questioned whether they have the requisite competence to try impeachments. All three judges challenged the legitimacy of trial committees, first in the Senate and later in federal court. They argued that the Senate’s “Power to try Impeachments” imposed on the full Senate—that is, all members—the obligation to conduct the 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, Walter Nixon v. United States (1993) held that the Senate’s power to try impeachments includes the final discretion to determine how to conduct its trials—a discretion that is not reviewable by judges.³⁶ The Supreme Court did not address whether the judiciary could review possible deviations from any explicit safeguard required by the Constitution for impeachment trials. The Court has yet to make clear what it might do, for example, if someone other than the Chief Justice presided over a presidential impeachment trial.³⁷

Constitutional Constraints on Impeachment Trials

What constraints, if any, does the Constitution impose on impeachment trials? In the 1980s, the Senate settled some procedural issues regarding the Fifth Amendment Due Process Clause. (See Essay No. 172.) Specifically, does the Due Process Clause limit 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. The Fifth Amendment had no bearing on the question. Rather, the Senate decided that each question was a matter for individual Senators to decide for themselves.

There is also some question about whether the First Amendment constrains the impeachment power. For example, can a President be impeached for engaging in arguably protected speech?³⁸ This issue arose during the impeachment trials of Presidents Johnson and Trump.³⁹

Late Impeachment

Can an officer who was impeached while in office but later resigned still be tried by the Senate? In other words, does the Constitution permit so-called late impeachment?⁴⁰ In England, anyone except for the king could be impeached for anything at any time. The Framers rejected such a free-wheeling form of impeachment and restricted it to “Officers of the United States.” Private citizens could not be impeached for their conduct as private citizens. In 1797, the House of Representatives impeached Senator William Blount of Tennessee. One day after the House impeached Blount, the Senate expelled him by a vote of 25 to 1. By the time impeachment proceedings began in the Senate, Blount was no longer in office. One of the House managers and Blount’s lawyer agreed that Blount was subject to impeachment even after leaving office,⁴¹ and the Senate proceeded to hold a trial.

A similar question arose eight decades later. In 1876, the House of Representatives was on the verge of impeaching Secretary of War William Belknap for bribery. Hoping to preempt his impeachment, Belknap rushed to the White House to submit his resignation, which President Ulysses S. Grant accepted. The House impeached Belknap anyway. Could the Senate try an officer who was no longer in office when he was impeached? The Senate voted 37 to 29 that Belknap was “amenable to trial by impeachment for acts done as Secretary of War, notwithstanding his resignation before he was impeached.”⁴² After the trial, the Senate voted to convict Belknap by a similar vote, which fell short of the two-thirds required for conviction.

The issue of late impeachment arose a third time more than a century later. On January 13, 2021, the House voted to impeach President Donald Trump. However, the articles of impeachment were not delivered to the Senate until January 25, five days after Trump left office. The first order of business confronting the Senate upon receiving the impeachment articles was whether it had jurisdiction to hold a trial for a President who was no longer in office. The House managers, Representatives Jamie Raskin and Joe Neguse, pointed to the Blount and Belknap precedents to support the Senate’s proceeding with a trial against Trump.⁴³ They argued that if the Senate did not retain jurisdiction over Presidents after they left office, they would be able to escape constitutional accountability for misconduct committed or discovered in the last few months, weeks, or days of their presidencies. David Schoen, counsel for President Trump, countered that the Framers rejected the British practice in which private citizens and former officials were subject to impeachment.⁴⁴ Rather, the Framers expressly restricted impeachment to “the President, Vice President, and all civil Officers of the United States.”⁴⁵ The Senate voted 56 to 44 to proceed with the trial; six Republican Senators joined all fifty Democrats.⁴⁶

Open Questions

• Is an official impeached when the impeachment vote is cast or when the articles are delivered to the Senate?⁴⁷
• What happens if the President is impeached and the Chief Justice cannot preside because of death, disability, resignation, recusal, or otherwise? Can the Senate designate another person to serve as Chief Justice?⁴⁸ Presumably, it can, because Senate rules allow for designation of the Senate President Pro Tempore as presiding officer when the Vice President is not available. In President Trump’s second impeachment trial, the Senate followed that procedure in recognizing President Pro Tempore Patrick Leahy as presiding officer. Would that designation be reviewable in federal court?⁴⁹
• During a presidential impeachment trial, does the Chief Justice or the presiding officer have the power to break a tie vote during a presidential impeachment trial? When the presiding officer is the Vice President, the Constitution settles that question by expressly empowering him or her to cast the tie-breaking vote in the Senate. When Senator Leahy presided over the second Trump impeachment trial, he followed Senate precedent, which allowed Senators when acting as presiding officers to cast separate votes.
• Does the Senate have a duty to hold an impeachment trial? Could the Senate simply ignore the articles entirely and not hold a trial? The clause does not clearly vest the Senate with discretion to hold a trial. Historically, in each instance in which a person has been impeached, the Senate has agreed to receive articles of impeachment and to take some action. In 2024, however, the Senate dismissed articles of impeachment against Secretary of Homeland Security Alejandro Mayorkas without holding a trial and resolved the matter based on briefs.

1. Peter Charles Hoffer & N.E.H. Hull, Impeachment in America 1635–1805, at 78 (1984). ↩︎
2. Id. ↩︎
3. 2 Farrand’s 159. ↩︎
4. Id. at 172. ↩︎
5. Id. at 177, 185–86. ↩︎
6. Id. at 493, 497. ↩︎
7. Id. at 499. ↩︎
8. Id. at 500. ↩︎
9. Id. at 551. ↩︎
10. Id. ↩︎
11. Id. ↩︎
12. Id. ↩︎
13. Id. at 552. ↩︎
14. Id. at 552–53. ↩︎
15. Id. at 495. ↩︎
16. Id. at 493, 592, 653. ↩︎
17. Hoffer & Hull, supra at 106. ↩︎
18. N.Y. Const. of 1777, art. XXXIII. ↩︎
19. Articles of Confederation, art. IX, § 6. ↩︎
20. Art. I, § 5, cl. 2. ↩︎
21. Art. II, § 2, cl. 2. ↩︎
22. 3 Farrand’s 148. ↩︎
23. Storing 2.6.45 ↩︎
24. Id. at 2.4.88. ↩︎
25. Id. ↩︎
26. Id. ↩︎
27. Your author served as Special Counsel to Senator Leahy during the second Trump impeachment trial. ↩︎
28. Joan Biskupic, John Roberts Ducks the Spotlight by Skipping the Second Trump Impeachment Trial, CNN (Jan. 26, 2021), https://perma.cc/YB58-AAT3. ↩︎
29. Michael J. Gerhardt, The Law of Presidential Impeachment: A Guide for the Engaged Citizen 59–60 (2024). ↩︎
30. Joan Biskupic, How the Last Chief Justice Handled an Impeachment Trial of the President of the United States, CNN (Dec. 1, 2019), https://perma.cc/U8VV-XMYS. ↩︎
31. Gerhardt, supra at 108–09. ↩︎
32. Biskupic, supra. ↩︎
33. Phil Mattingly et al., John Roberts Publicly Rejects Rand Paul’s Whistleblower Question in Senate Impeachment Trial, CNN (Jan. 30, 2020), https://perma.cc/2CSZ-YRFM. ↩︎
34. Pete Williams, Chief Justice John Roberts Says He Won’t Break Tie Votes in Senate Impeachment Trial, NBC News (Jan. 31, 2020), https://perma.cc/TYN8-YFBC. ↩︎
35. Jefferson’s Manual of Parliamentary Practice, in H. Doc. 117-161, 17th Cong., 131–345 (2023). ↩︎
36. 506 U.S. 224, 230 (1993). ↩︎
37. Adam Liptak, Can Trump Challenge His Impeachment in the Supreme Court?, N.Y. Times (Nov. 25, 2019), https://perma.cc/5QSN-BTSN. ↩︎
38. Katherine Shaw, Impeachable Speech, 70 Emory L.J. 1 (2020). ↩︎
39. Josh Blackman & Seth Barrett Tillman, We Should Not Forget the Free Speech Lessons from President Johnson’s Impeachment Trial, Volokh Conspiracy (Jan. 14, 2021), https://perma.cc/6SDL-YGVK; Keith E. Whittington, Is There a Free Speech Defense to an Impeachment?, Lawfare (Jan. 19, 2021). ↩︎
40. Brian C. Kalt, The Constitutional Case for the Impeachability of Former Federal Officials: An Analysis of the Law, History, and Practice of Late Impeachment, 6 Tex. Rev. L. & Pol. 13, 17 (2001). ↩︎
41. Laurence H. Tribe, The Senate Can Constitutionally Hold an Impeachment Trial After Trump Leaves Office, Wash. Post (Jan. 13, 2021). ↩︎
42. The Impeachment and Trial of William W. Belknap, in 3 Hinds’ Precedents §§ 2444–68. ↩︎
43. 167 Cong. Rec. S591–97 (2021). ↩︎
44. Id. at S601–08. ↩︎
45. Art. II, § 4; 167 Cong. Rec. S606 (2021). ↩︎
46. 167 Cong. Rec. S609 (2021). ↩︎
47. Adam Liptak, A Law Professor’s Provocative Argument: Trump Has Not Yet Been Impeached, N.Y. Times (Dec. 20, 2019), https://perma.cc/8W7D-7V8J. ↩︎
48. Josh Blackman & Seth Barrett Tillman, Could Justice Thomas Preside over President Trump’s Impeachment Trial?, Balkinization Blog (Nov. 17, 2019), https://perma.cc/J7L4-BSUU. ↩︎
49. Josh Blackman, What Happens If the Chief Justice Cannot Serve at the Presidential Impeachment Trial?, Volokh Conspiracy (Nov. 25, 2019), https://perma.cc/BR7Z-7HJH. ↩︎