In the 15 months that followed the election, the A.C.L.U.’s membership went from 400,000 to 1.84 million. Online donations in the years before averaged between $3 and $5 million annually. Since then, it has raised just shy of $120 million. “Until Trump,” Romero told me, “most of our support came from people who have been with us since we challenged Nixon. Now we’re kind of cool. Cool’s not a word generally associated with us.”

In the latest string of celebrity fund-raisers, for instance, Radiohead announced that anyone who makes a $10 donation to the A.C.L.U. will be entered into a lottery to hang out with the band and get V.I.P. tickets to a show. Back in March 2017, Tom Hanks, Tina Fey and Alec Baldwin were among the hosts for a Facebook Live telethon that raised more than half a million dollars and was nominated for an Emmy. That same spring, Zedd, a German house DJ, organized a benefit at the Staples Center in Los Angeles. Gelernt was one of a handful of A.C.L.U. representatives who addressed thousands of fans between acts. “I went on after Imagine Dragons,” he told me. “It was insane. I put on sunglasses and went out there and started talking, and I couldn’t see anything. Then I go backstage, and these musicians who are practically my kids’ age are partying and asking what we’re doing to resist Trump. I was like, ‘Well, there’s an en banc hearing in the Fourth Circuit coming up.’ ”

A big chunk of the money that the A.C.L.U. has raised has gone toward hiring more lawyers, both in the national office and throughout its network of 54 affiliates.