Mueller did not attend, and the attorney general said he didn’t talk to Mueller about his decision to clear Trump of obstruction. “That’s not two friends collaborating collegially on a project,” said Frank Figliuzzi, a former counterintelligence chief at the FBI who briefed Mueller twice a day during their tenure together. “It’s almost worse than undercutting Mueller. It’s saying Mueller’s not even relevant in this.”

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In a phone interview, Figliuzzi described the dynamic between Mueller and Barr as one of “a boy scout” (Mueller) versus “a street fighter” (Barr). The attorney general himself has acknowledged that he and Deputy Attorney General Rod Rosenstein “disagreed with some of the special counsel’s legal theories.” Now it is up to Congress to sort through the conflicts and to determine the legacy of the investigation they each had a hand in steering. “Mueller is a guy who plays by the rules, and he was playing by the rules in this report,” Figliuzzi told me. “He kind of trusts that the system will take care of itself, and he kicks his report over across the street to DOJ. That’s where things go south.”

It was Barr who first brought up his decades-long friendship with the man whose investigation he was to oversee, whose conclusions he was to summarize, and whose report he was to present to Congress and the American public. “I have known Bob Mueller personally and professionally for 30 years,” he told the Senate Judiciary Committee in January. “We worked closely together throughout my previous tenure at the Department of Justice under President Bush. We’ve been friends since.”

When Barr served as attorney general under President George H. W. Bush in 1991 and 1992, Mueller was the assistant attorney general heading up the criminal division. Both Barr and Mueller were in their 40s at the time, and colleagues from that period describe them as exceptionally smart and well-prepared lawyers who shared an easy rapport with each other, as well as a reverence for the Department of Justice. “Bob has always had this real strong desire to see the rule of law vindicated. That’s where the two of them are two peas in a pod,” said Paul McNulty, who served as the department’s chief spokesman in the early 1990s and later oversaw Mueller as deputy attorney general in the George W. Bush administration.

Barr and Mueller would sit in daily morning meetings in which Barr would often rib the more straitlaced Mueller about cases. “They got along very well,” recalled Timothy Flanigan, who was then an assistant attorney general overseeing the Office of Legal Counsel. “Bill had a keener sense of humor than Bob. He’d poked fun at Bob, and Bob took it in good grace.”

Mueller, a Marine who became a prosecutor, and Barr, who had worked in policy jobs during the Reagan and Bush administrations, were aligned on the tough-on-crime priorities that were in vogue in the early 1990s. Separately, former colleagues described each of them as the kind of boss who doesn’t “suffer fools.” But they had different strengths and different personalities. “One’s a soldier, one was essentially an intellectual, legal heavyweight,” McNulty told me. While Barr was known as a quick thinker who thought through arguments and made decisions rapidly, Mueller was more deliberative and process-oriented. “Mueller could be more down in the weeds,” McNulty said, “and Barr was more up above the weeds, looking at the constitutional issue, the big legal issue.