The Chief Justice of the United States presides over a presidential impeachment trial in the Senate. Article I, Section 3 of the Constitution says so directly: “When the President of the United States is tried, the Chief Justice shall preside.”1Constitution Annotated. Article I, Section 3, Clause 6 That requirement kicks in only when a sitting president is the defendant. Every other impeachment trial, including one of a former president, is run by the Senate’s usual presiding officer.
Why the Chief Justice Instead of the Vice President
The Vice President is normally the president of the Senate.2United States Senate. About the Vice President Putting that person in charge of a trial that could remove the president and elevate them to the job would be an obvious conflict of interest. The framers pulled in the head of a separate branch instead. The Chief Justice sits outside the line of succession and carries no political stake in the verdict.
The Senate made the same point during the second Trump impeachment, explaining that “it would be a conflict for someone to preside over a trial that would become President if there was a conviction.”3Congress.gov. Congressional Record, February 9, 2021
What the Chief Justice Actually Does
The role sounds commanding but is heavily constrained. Under Senate Rule VII, the presiding officer “shall direct all the forms of proceedings” and “may rule on all questions of evidence including, but not limited to, questions of relevancy, materiality, and redundancy.” The Chief Justice also administers the oath to each senator, who must swear to “do impartial justice according to the Constitution and laws.”4GovInfo. Rules of Procedure and Practice in the Senate When Sitting on Impeachment Trials
Here the role parts ways with an ordinary judge. Any single senator can challenge a ruling, and a simple majority can overturn it.4GovInfo. Rules of Procedure and Practice in the Senate When Sitting on Impeachment Trials The Chief Justice can also decline to rule at all and put the question straight to the Senate. There is no Federal Rules of Evidence to lean on, no appellate court above the Senate’s verdict.5Legal Information Institute. Senate Practices in Impeachment In practice, the Chief Justice keeps the proceedings orderly while the senators act as judge and jury.
Chief Justice William Rehnquist, after presiding over the Clinton trial, said he “did nothing in particular, and did it very well.” The line captures the job.
When the Chief Justice Does Not Preside
The constitutional text is narrow. It requires the Chief Justice only “when the President of the United States is tried.” For any other impeachment target, a federal judge, a cabinet secretary, or a former president, the Senate’s normal presiding officer runs the trial. That is the Vice President or, more often, the president pro tempore.6Constitution Annotated. ArtI.S3.C6.2 Historical Background on Impeachment Trials
That distinction became a live question in February 2021. Donald Trump had already left office, and Joe Biden was the sitting president when the Senate tried Trump a second time. Chief Justice John Roberts did not preside. Senator Patrick Leahy, then the president pro tempore, did. The Senate’s reasoning: “There is only one person who is President of the United States at a time. Right now, Joseph R. Biden, Jr., is the 46th President of the United States. As a result, the requirement that the Chief Justice preside isn’t triggered.”3Congress.gov. Congressional Record, February 9, 2021
The Four Presidential Impeachment Trials
Only four presidential impeachment trials have been held, and the presiding officer question broke the pattern in the fourth:
- Andrew Johnson (1868): Chief Justice Salmon P. Chase presided. The Senate acquitted by one vote.
- Bill Clinton (1999): Chief Justice William Rehnquist presided. Acquitted on both articles.
- Donald Trump, first trial (2020): Chief Justice John Roberts presided. Acquitted on both articles.
- Donald Trump, second trial (2021): Senator Patrick Leahy, president pro tempore, presided because Trump was no longer the sitting president. Acquitted.
No sitting president has ever been convicted and removed.