If President Donald Trump is impeached, it will ultimately be senators who decide whether or not to remove him from office.

But there’s one other key figure in an impeachment trial: Chief Justice John Roberts, who has presided over the most right-wing Supreme Court in decades — and who would preside over the trial in the Senate.

As Constitutional Accountability Center president Elizabeth Wydra told MSNBC anchor Alex Witt on Saturday, this would be a critical, and uncomfortable, moment for Roberts in his career.

“What can we expect from Supreme Court Chief Justice John Roberts?” asked Witt. “Are there any clues from what you have observed from him on the bench?”

“Absolutely,” said Wydra. “So Chief Justice Roberts has made great pains to paint himself and his court as above politics. He does not like them to be seen, as President Trump often tries to paint them, as political actors. President Trump has said over and over on Twitter he views the Supreme Court and the chief justice in his pocket, perhaps his literal get out-of-jail-free card, and Chief Justice Roberts loathes that sort of thing. He’s been clear he does not want himself and his fellow justices to be seen that way.”

“In this crucial moment of constitutional democracy, he will go out of his way to try to be above politics,” predicted Wydra. “You know, to try to follow the role perhaps of Chief Justice Rehnquist when he presided over the Clinton impeachment trial in the Senate, to, as Rehnquist said, ‘Do as little as possible and do it very well.’”