According to the New York Times, special counsel Robert Mueller has four dozen questions he wants to ask President Donald Trump about the Russia investigation. At least 18 of them focus on James Comey, the man Trump fired as FBI director last year in a failed attempt to “lift the cloud” of the investigation. Many of the questions involve meetings between Trump and Comey. Comey says Trump pressed him for personal loyalty and asked him to drop his investigation of then–National Security Adviser Mike Flynn. Trump denies it. It’s Trump’s word against Comey’s.

That’s why Trump has relentlessly attacked Comey’s credibility since he fired him. On Saturday night, at a rally in Michigan, Trump again called Comey “a liar and a leaker” for disclosing, in contemporaneous memos, the contents their meetings. Trump mocked the interviews Comey has given in recent weeks about the former director’s new book, A Higher Loyalty. “Watch the way he lies,” said Trump.

By all means, watch Comey’s interviews. They’ll give you a chance to hear directly from the man whose testimony could put Trump away for obstruction of justice. We know Trump has a long record of fabrication and delusion. But what about Comey? How does he conduct himself when pressed to answer hard questions?