In his first weeks as a federal judge in Washington last December, Amir Ali was surprised to learn that the job didn’t come with a robe. Where was he supposed to get one? He had to order his own, and it would take months to arrive.

There was much that Ali, as a brand-new member of the federal bench, did not yet know. A lot of it would be covered at a five-day orientation program for new appointees hosted by the Federal Judicial Center and affectionately referred to as “baby judges school,” but that takes place only a few times a year, and the next session was months away. Ali would have to learn the job by doing it and from senior judges on his court, the U.S. District Court for the District of Columbia. When word got around that he was waiting for his robe, he found one on his desk with a note from a former chief judge: “Yours as long as you need it.”

The D.D.C., as the court that Ali joined is called, has one of the highest profiles of the 94 federal District Courts across the country. Its location makes the D.D.C. the frequent starting place for suits against the federal government and thus the site of numerous historic showdowns. It was D.D.C. judges, in the 1970s, who ruled that the Pentagon Papers could be published and ordered Richard Nixon to turn over the Watergate tapes.

Ali, whom the Senate confirmed shortly after Donald Trump won the presidential election, was one of Joe Biden’s last judicial nominees. In his first couple of weeks, Ali met his three law clerks in person for the first time (he hired them over Zoom) and started sorting through the 226 cases he inherited from other judges. It was a whirlwind. But he had the guidance of some of the D.D.C.’s senior judges, who like many of their counterparts in other federal courts see themselves as stewards of a tradition of nonpartisan collegiality and decision-making. “They have the perspective that comes with having been through other complicated historical times,” says James Boasberg, the D.D.C.’s chief judge.

Once Trump became president, Ali and his colleagues faced a level of pressure unlike any in the modern era.

One senior judge who helped get Ali situated was Royce Lamberth, an 81-year-old Reagan appointee from Texas who was chief judge of the D.D.C. from 2008 to 2013. “One reason I keep hanging on is that I love working with new judges,” Lamberth explained. “I don’t care how liberal they are, and they don’t care how conservative I am.” Many afternoons during his first months in the job, Ali would stop by Lamberth’s chambers, which were on the same floor as his, passing under a pair of cattle horns mounted above an inner doorway.