Lee Gelernt looked both thrilled and disoriented. The American Civil Liberties Union lawyer, normally a household name only in his own household, had emerged from a federal courthouse in Brooklyn to find 2,000 protestors cheering him.

The 54-year-old Gelernt and his colleagues had just won an emergency Saturday night stay of President Donald Trump’s executive order banning most travelers from seven majority-Muslim countries. And while the civil liberties lawyer in the nondescript gray suit and the proudly-nerdy black-framed glasses was ecstatic over the victory, Gelernt was exhausted by the work that had gone into it.

“We knew there was gonna be this Muslim ban, and we started gearing up after Trump was elected, but we thought we would be challenging the ban for people stopped at airports overseas,” he said, standing in a park near the Brooklyn Bridge as colleagues tried to find a bar in which to celebrate. “Trump signed the order at about 4:45 Friday afternoon. We didn’t expect that people en route to the U.S. when he signed the order would be detained. I start getting emails around 10 o’clock from the International Refugee Assistance Project saying there may be trouble at JFK with two of their clients who are Iraqi nationals. So people worked all night and we filed a complaint at 5:53 a.m. Saturday. Then at noon we started writing emergency stay papers to try to prevent people from being deported before the judge could rule on the legality of Trump’s order.”

The haste and sloppiness of Trump’s decree handed the ACLU a short-term legal and political gift. Had the executive order been written more coherently, and rolled out with greater coordination, it wouldn’t have provided the potent symbolism of women, children, and people who’d risked their lives to help the U.S. military being locked up—and it wouldn’t have provoked thousands of demonstrators to clog American airports or goaded judges to act quickly to stop it. “But we’re not kidding ourselves,” said Omar Jadwat, who had been in the courtroom as Gelernt’s ACLU co-counsel. “It’s just the beginning. Immigration and litigation—that’s the American way.”

Indeed. And now that a three-judge panel of the Ninth Circuit Court of Appeals in San Francisco has upheld the lower court decisions that stalled Trump’s travel ban, the legal action and the spotlight will shift to Washington and the Supreme Court. Yet the ACLU’s initial scramble to redirect its counterattack is an important preview of the larger challenge the organization faces. Can it stay nimble for the next four years?

Last summer David Cole agreed to join the ACLU as its national legal director, starting in January 2017. Even before he was officially on board, though, Cole and his soon-to-be-staff spent months getting ready for a Hillary Clinton administration, and for the happy prospect of expanding progressive rights. “We had a number of memos prepared on what a Supreme Court might look like with a liberal majority for the first time in 45 years,” Cole says with a rueful laugh. A single 27-page memo explored the remote contingency of what might be legally necessary if Trump won.

Three days after the election the ACLU went on the public relations offensive, with a full-page ad in The New York Times telling Trump, “We’ll see you in court.” On Inauguration Day, the ACLU filed Freedom of Information Act requests seeking documents that could expose conflicts of interest between President Trump and businessman Trump. More quietly, the ACLU has stepped up its efforts to persuade mayors and police chiefs to avoid taking on federal immigration duties, in an attempt to counter Trump’s efforts to ramp up deportations.

Being aggressive has been good for the ACLU’s image—and great for its budget. The ACLU is suddenly awash in money and members. More than $79 million has been donated to the group since Election Day, with $31 million of it arriving during the 24 hours immediately after Trump signed the travel ban. “We have already hired about a dozen people,” Cole says. “We have 300 lawyers right now. Maybe we’ll go up to 350, 400. And our advocacy and communications staff will certainly increase.”

Gelernt points out that the Justice Department will always have more lawyers, even after the ACLU goes on a hiring spree. (His younger sister is currently battling the government in a very different arena: Michelle Gelernt, a federal public defender, is representing Joaquín “El Chapo” Guzmán.) “But to the extent we can even it out a little bit, that’s why all these private law firms volunteering help, all these law students staying up all night, are important,” he says. “And we are now looking at one of those classic civil rights movements, where it’s not just the lawyers in court making technical arguments. It’s the combination of legal work and an enormous outpouring of the community. That support is essential, if any real civil rights work is going to be successful.”

There’s encouraging news on that front as well: The ACLU membership rolls have doubled, to 1 million, which could translate into more political muscle. “That gives us a tremendous opportunity, in terms of activating those members, directing them to take action,” Cole says.

But the group’s leaders acknowledge they’re playing defense and feeling a bit off-balance. Trump, by virtue of calculation as well as his congenital impatience, is moving, with the help of Congress, on multiple constitutionally dubious fronts at the same time: reproductive rights, voter rights, libel laws, the torture of terrorism suspects, as well as immigration rights. The range and quantity of issues could make defending individual civil liberties infringements more difficult for the ACLU. Especially as the Trump administration, after stumbling out of the gate, becomes more efficient at pursuing its agenda.

“There’s going to be a critical need for us to triage and pick the most important things,” Gelernt, the deputy director of the ACLU’s Immigrants’ Rights Project says. “I don’t think we’re going to get distracted or cave under the sheer weight of the policies the administration is putting out there. But I suspect that’s one of their goals.” He also wonders if the ACLU’s hard work could end up being beside the point. “One of the critical aspects going forward will be, Is Trump going to comply with court orders? In some ways, that’s a much bigger issue. If they don’t, then you’re talking about a real constitutional crisis.”

Whether the ACLU can handle its newfound popularity and prosperity is a more immediate and less theoretical question. Shortly after Gelernt and Jadwat prevailed in Brooklyn federal court, the ACLU’s national political director did some premature end-zone dancing: “I hope Trump enjoys losing,” Faiz Shakir told Yahoo News. “He’s going to lose so much we’re going to get sick and tired of his losing.” For now, groups like IRAP, the National Immigration Law Center, and Yale Law School’s Worker & Immigration Rights Advocacy Clinic have allowed the ACLU to take the lead against Trump’s travel ban, but sharing credit and blame as more cases reach court will test those alliances. As the 2018 and 2020 elections get closer, the interests and strategic choices of the ACLU and the Democrats could well diverge on contentious issues like flag burning.

And Cole knows that all those new ACLU members and donors want something in return for their investment of time and money, and that the quick, seemingly easy initial win in Brooklyn also raises the stakes. “There’s absolutely a sense of pressure,” Cole says. “We need to deliver. We need to be responding to the people who are reaching out to us. We need to show them what we’ve done to stand up in the fight against Donald Trump.”

Not that he and others weren’t already taking Trump’s policies and tactics seriously and personally. As a lawyer, Cole was dismayed when Trump hurled a bullying series of tweets at the Seattle federal court judge who ruled against the administration’s travel ban, preemptively assigning responsibility for any future terrorist acts. As the husband of a federal judge himself, though, he was alarmed.

“Yes, it is worrisome to me,” says the 58-year-old Cole, who is married to Judge Nina Pillard of the U.S. Court of Appeals for the D.C. Circuit. “The president of the United States has a responsibility to respect the separation of powers and the roles that the various branches play. And his utter disrespect for judges who disagree with him is deeply concerning. I can’t psychoanalyze Trump, but I will say this: Nothing is more likely to get the backs up of judges than the president attacking a judge because he doesn’t like his decision. If it was tactical, it was very ill-advised.”

Omar Jadwat, 43, the director of the ACLU’s Immigrants’ Rights Project, is a first-generation American. “It’s a blessing to do something you believe in for a job. That’s always the case. But I think there’s something uniquely offensive about this ban,” he said, moments after winning the first round in federal court. “I was born in Queens. My dad grew up in South Africa as a person of color. My mother is from Korea. The story of leaving oppression in your homeland to come to America is one that’s embedded in my family literally, as in so many others.”

Jadwat paused and looked back at the Brooklyn courthouse, trying to get his bearings as the dispersing protestors swirled around him in the darkness. “As in Jared Kushner’s family.”