Earning a clerkship in the U.S. Supreme Court is an experience of a lifetime, but expand it to include a presidential impeachment trial and the historical significance of that experience is beyond any expectations.

Megan Braun, a clerk to Chief Justice John Roberts Jr., will be near her boss Tuesday, ready to assist with any needed legal research, during the Senate impeachment trial of President Donald Trump.

Roberts' impeachment duties began in earnest Tuesday afternoon with opening statements by House managers and Trump's legal team led by White House Counsel Pat Cipollone and the president's personal lawyer Jay Sekulow.

The chief justice delivered the oath to Oklahoma Republican Sen. James Inhofe, who was absent last week when the other senators swore to deliver impartial justice on charges that Trump abused the power of his office and obstructed Congress.

The chief justice then settled in for what could be a very late night. He might face his first request for a ruling on a controversial matter—Senate Democratic Leader Chuck Schumer's request for a subpoena of all documents within the White House's control relating to the president's contacts with Ukraine's new president. That request is likely to be voted on by the full Senate.

Whether Roberts's three other clerks will get to experience some of the trial is not yet clear, but Braun won't be alone in assisting the chief justice. Jeffrey Minear, longtime counselor to the chief justice, is also helping Roberts, the court said. Roberts said last week he expects "business as usual" at the Supreme Court as he pulls double-duty.

Braun, a 2016 Yale Law graduate, has the golden resume of most Supreme Court clerks. Besides the ivy league law school credential, she is a Rhodes scholar, a 2013 Oxford University graduate with a master's in philosophy and international relations, and a 2010 graduate of the University of California-Irvine with a bachelor's in history.

Before joining Roberts' chambers, Braun was a Bristow Fellow in the U.S. Justice Department's Office of the Solicitor General from July 2018 to July 2019. She actually had even earlier experience in that office as a summer law clerk for three months in 2016.

Braun moved from that summer clerkship to a clerkship with U.S. District Judge Leonie Brinkema of the Eastern District of Virginia. After her clerkship with Brinkema, she went to clerk for Judge Robert Katzmann of the U.S. Court of Appeals for the Second Circuit and then on to Roberts.

Earlier in her legal education, Braun held summer positions at the Justice Department's national security division and at the Department of State's Office of the Legal Adviser. She also worked at Sullivan & Cromwell.

At Oxford, Braun's research focused on the interaction among technology, law, and the just war tradition. Among her publications were: "Where Rand Paul and John Brennan can agree on the US drone program;" "Shadow War: A History of the CIA's Predator Drone Operations," and "The Obama Doctrine: Drones and Just Wars."

During the impeachment trial of President Bill Clinton, then-Chief Justice William Rehnquist also was assisted by a law clerk. But all three of his clerks did get to experience some of that historical event, according to one of three who was there, Robert Schaffer of Holden Willits in Phoenix.

Schaffer said that "at least one of us was with the chief at all times while he was over at the Senate. Sometimes two of us attended. During the closed deliberations and final votes, all three of us attended, if I recall correctly." He said the three clerks attended the final votes.

The other two Rehnquist clerks were Neil Richards of Washington University St. Louis School of Law and Christopher Bowers, partner at Skadden, Arps, Slate, Meagher & Flom in Washington.

Former Senate Sergeant at Arms James Ziglar, in an interview with NPR, recalled how Rehnquist chaffed at breaks in the Clinton trial that lasted well past the time announced by the Senate majority leader. During one of those breaks, Ziglar said he once found Rehnquist sitting in the Senate room assigned to them and playing poker with his clerks.

Jeffrey Minear Jeffrey Minear, counselor to Chief Justice John Roberts Jr. Photo: Diego M. Radzinschi / ALM

Minear, a former assistant to the U.S. solicitor general who has argued 56 high court cases, has been Roberts' counselor since 2006. He assists the chief justice in overall management of the court. Roberts also is expected to rely heavily on Senate Parliamentarian Elizabeth MacDonough, the court said last week.