Article I, Section 3 of the U.S. Constitution states that "the Senate shall have the sole Power to try all Impeachments," and "when the President of the United States is tried, the Chief Justice shall preside." John Roberts, the Chief Justice of the Supreme Court, is refusing the preside over the impeachment trial of Donald Trump. Thus, Democratic Senator Patrick Leahy (VT), who previously voted to impeach Trump, is slated to preside over the trial.