U.S. Constitution – Article 2 Section 4
The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.
U.S. Constitution – Article 3 Section 2
In all Cases affecting Ambassadors, other public Ministers and Consuls, and those in which a State shall be Party, the supreme Court shall have original Jurisdiction. In all the other Cases before mentioned, the supreme Court shall have appellate Jurisdiction, both as to Law and Fact, with such Exceptions, and under such Regulations as the Congress shall make.
The Trial of all Crimes, except in Cases of Impeachment, shall be by Jury; and such Trial shall be held in the State where the said Crimes shall have been committed; but when not committed within any State, the Trial shall be at such Place or Places as the Congress may by Law have directed.
Newsweek – BY
Senator Pat Leahy, the president pro tempore of the Senate, will preside over former President Donald Trump’s second impeachment trial, not Chief Justice John Roberts, who presided over Trump’s first trial.
Traditionally, the Supreme Court fulfills the role of presiding over a president’s impeachment trial because it’s outlined in the Constitution. However, this is the first time a president will be tried after he’s left office, so that responsibility will fall on Leahy, according to a Senate source.
While Leahy presiding over the trial is unprecedented and may seem to break from tradition, the Senate source told Newsweek it’s because senators preside over the trial if the impeached is “not president of the United States.”
The Constitution specifies that when the president is the accused, “the Chief Justice shall preside.” Part of the reason for this specification is because there’s an obvious conflict of interest with the vice president, who normally serves as president of the Senate, presiding over the impeachment trial when a conviction means they’d take over as president.
There’s been some debate as to whether Roberts should preside over Trump’s trial despite him not being in office, but without any precedent, it’s been left up to legal interpretation. There doesn’t seem to be a consensus among legal scholars as to who should preside over the trial, and the decision was left up to congressional leaders.
Despite them being labeled liberal or conservative and nominated by presidents of a certain party, Supreme Court justices are considered politically neutral entities, making them the most likely to be an independent judge. Senators, however, are not and some have taken issue with the prospect of Leahy presiding over the trial after casting a vote to convict Trump the first time he was tried.
Others have criticized the trial for being unconstitutional since Trump is no longer in office.