“I think it is appropriate at this point for me to admonish both the House managers and president’s counsel in equal terms to remember that they are addressing the world’s greatest deliberative body,” Roberts said, in a rare comment. “Those addressing the Senate should remember where they are.”

Roberts’ remarks came after a sharp exchange between House impeachment manager Jerry Nadler (D-N.Y.) and White House Counsel Pat Cipollone, amid debate over Senate Minority Leader Chuck Schumer’s amendment to subpoena former national security adviser John Bolton.

Nadler, the House Judiciary Committee Chairman, accused Senate Republicans of wanting to participate in a cover-up by blocking additional witnesses and documents.

“History will judge and so will the electorate,” he said, prompting groans from Senate Republicans in the chamber.