The pattern was set for the rest of the investigation — and the rest of Mr. Garland’s career: painstaking work behind the scenes and extreme rhetorical restraint in public. A few days after he arrived in Oklahoma, Mr. Garland served as prosecutor in Mr. McVeigh’s bail hearing. In light of the seriousness of the charges, there was no chance Mr. McVeigh was going to be released, but Mr. Garland went out of his way to speak about the case in an almost willfully boring way. “You have heard evidence, your honor,” he said in court, “more than sufficient to establish that during and in relation to a crime of violence the defendant used and carried a destructive device — that is, a bomb.” On the issue of bail, he said: “Your honor, as everyone knows, he faces the possibility of the death penalty in this case and enormous incentive to flee. The government represents no condition would prevent a person in that situation from fleeing.”

Mr. Garland became so invested in the bombing case that he weighed asking Ms. Gorelick for the chance to remain as lead courtroom prosecutor. But his boss had other plans, because the Unabomber investigation was floundering. Starting in 1978, a series of bombs had been mailed to various university and airline targets around the country. From 1987 to 1993, the bombings ceased, but then they started up again, including one that killed a Sacramento man on April 24, 1995, five days after the Oklahoma City bombing. The Justice Department was embarrassed by its failure to catch the mysterious perpetrator, and Ms. Gorelick told Mr. Garland to take over, which he did. (Ted Kaczynski was arrested for the bombings in his tiny cabin in Montana on April 3, 1996.)

For the trials of Mr. McVeigh and Terry Nichols in the Oklahoma City bombing, Mr. Garland helped select a prosecution team led by Joseph Hartzler and Larry Mackey, who never became as famous as the O.J. prosecutors but who won convictions in court. (Mr. McVeigh was executed in 2001; Mr. Nichols is serving life without parole.) Mr. Garland received a splendid consolation prize for losing out on the trials. In September 1995, President Bill Clinton nominated him to a seat on the United States Court of Appeals for the District of Columbia Circuit, the second most important court in the country, though he was not confirmed until March 1997. Mr. Garland’s tenure as a judge reinforced the tendencies he established in the bombing investigation: meticulous about assembling facts and reluctant about expressing views.

So it has gone in Mr. Garland’s turn as attorney general, especially when it comes to the Trump investigation. Since taking office, Mr. Garland has been criticized for the slow pace of the investigation and for his failure to prosecute those who inspired or incited the Capitol attack as he focuses instead on those who invaded the building. This criticism seems unfair, or at least premature. Mr. Garland has hardly backed away from the post-Jan. 6 investigation. He sanctioned the prosecution of the Proud Boys and the Oath Keepers on the rarely deployed charge of seditious conspiracy; approved the search of Mar-a-Lago, Mr. Trump’s home in Florida; and appointed Jack Smith, an aggressive prosecutor, to lead the investigations. A fair verdict on Mr. Garland should await the outcome of Mr. Smith’s work.

Yet it is fair to question why Mr. Garland continues to be a quiet, if not silent, public voice about the Trump investigation. “We follow the facts and the law wherever they lead,” he said at the Justice Department podium. “The best way to undermine an investigation is to say things out of court.” This is actually a debatable point. Government officials, especially high level policymakers like the attorney general, are allowed to speak publicly about the meaning and importance of their work, including the continuing threat of homegrown violence. (In my interview with him, Mr. Garland not only refused to draw any comparisons between Mr. McVeigh and the Capitol rioters but also refused even to utter the words “January 6.”)