Late Saturday night, in the jam-packed baggage terminal for international arrivals at Washington Dulles International Airport, dozens of lawyers and hundreds of protesters watched as the first major Constitutional crisis of the Trump presidency played out.

The day before, Trump signed an executive order barring people from seven majority-Muslim countries from entering the United States. But many people traveling to the U.S. from those countries—including legal permanent residents of the U.S.—were already in the air and couldn’t turn around. As a result, airports across the country turned into lawfare zones, with cadres of volunteer lawyers squaring off against bureaucrats in the Customs and Border Protection agency. Late-night rulings from federal judges made a legally unprecedented situation even more dramatic, with all three branches of the federal government—legislative, executive, and judicial—warring with each other. At stake: the lives and safety of people trying to legally enter the U.S.

At about 7:30 p.m., a boisterous crowd of several hundred pro-refugee protesters had circled around the “International Arrivals” baggage claim at Dulles—flanked by police who cleared a passageway so people getting off planes could get through. Protesters waved signs saying refugees were welcome (some signs read “Welcome” in Arabic), denouncing President Trump, and calling for Christians to show Christlike love to people fleeing terrorism. They carried “Welcome Home” balloons and they sang songs.

And there were chants, including “Let them see their lawyers now!”

There were dozens of lawyers, brought together by the International Refugee Assistance Project. A handful actually practiced immigration law, and dozens more with non-immigration backgrounds—bankruptcy, litigation, you name it—showed up to try to help.

Early in the evening, a huge piece of news broke: Two federal judges, Ann Donnelly of the Eastern District of New York and Leonie Brinkema of the Eastern District of Virginia, had made rulings that would stall the implementation of Trump’s anti-refugee executive order.

For the lawyers at Dulles Airport, Brinkema’s ruling generated a ton of excitement. She ruled that the travelers detained by Customs and Border Protection (CBP) had a right to see lawyers.

After the ruling came out, lawyers bustled around, filling out forms declaring that detainees were their clients (someone had thought to bring a printer). Any minute, they expected, they would be able to see the detainees and try to help them get into the U.S.

At this point, it wasn’t clear how many people were detained and which of them were legal permanent residents of the U.S. Lawyers didn’t even know all the names of the people they were trying to help. It wasn’t clear if some detainees had been put back on planes returning to their countries of origin, or if detainees had been shuttled off to immigrant detention centers in Northern Virginia. The travelers were all being held in what’s called “secondary inspection,” referred to as “secondary.” It’s part of the CBP screening process where lawyers are rarely, if ever, allowed to be present.

But lawyers who spoke to The Daily Beast said it’s also unheard of for government agencies like CBP to prevent people who have the legal right to live in the U.S. from seeing their lawyers. And that’s what was happening.

After Brinkema’s order came down, and lawyers at Dulles prepared to meet their new clients, the CBP balked, barring these lawyers from seeing their would-be clients.

Time ticked. Protesters chanted. CBP officials were invisible; for hours, lawyers didn’t know if CBP officials at Dulles had even acknowledged Brinkema’s ruling existed.

Lawyers wrung their hands. And then, slowly, detainees started trickling out, one or two at a time. One woman who had been detained doubled over sobbing as she walked through the crowd. She nearly collapsed onto a loved one. Another man who was detained, Javad Fotouhi, calmly fielded questions from a scrum of reporters about the four hours he spent in secondary. When CBP finally let him go, he said, they didn’t say why.

“We saw elderly people and disabled people,” he said.

Then two wheelchair-bound people—an 88-year-old man and his 83-year-old wife, both of whom have green cards, according to their granddaughter—came out. Their granddaughter, Pegah Rahmani (an American citizen who lives in Fairfax, Va.) doubled over to hug them. She told The Daily Beast that her grandmother had recently had a stroke and her grandfather was legally blind.

“They really weren’t treating them very nicely,” she said, of their time in detention. “They took a lot of their stuff.”

That included medication; neither of the feeble octogenarians had access to their meds, much less to lawyers.

Another Iraqi man who was detained made a beeline out of the airport as soon as he was set free. Standing at the curb, he lit up a thin cigarette and told reporters that there was a family still detained, including a wheelchair-bound young woman with mental disabilities.

As the night wore on, it became increasingly clear that CBP was defying Brinkema’s ruling. Lawyers concluded that that meant someone was in contempt of court. The judge could theoretically send in federal law enforcement officers to force CBP to let the lawyers meet with the detainees. But sending in the U.S. Marshals—who are part of the Department of Justice—to take on Customs and Border Patrol—which is part of the Department of Homeland Security—would have been a bureaucratic clash of the titans. And, like everything else that night, it would have been unprecedented. It didn’t happen.

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Though detainees were slowly being released, lawyers were disturbed that they couldn’t meet with them. What if CBP tried to coerce detainees into signing paperwork that could jeopardize their legal status? Release wasn’t enough. A federal agency was defying a federal judge, and no one was quite sure what to do.

Then at around 11:45 p.m., New Jersey Senator Cory Booker showed up.

He had come to get the travelers out of detention, “or at least access to an attorney,” he told The Daily Beast.

Then he disappeared down a hallway blocked off by police, back to where the CBP officials had quarantined themselves.

Booker stayed back there for about half an hour, and then he pushed through the crowd of roaring protesters and—flanked by glowering policemen—addressed the crowd. After a few opening words, he held up a copy of Brinkema’s order.

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“I am now of the belief that though this was issued by the judicial branch, that it was violated tonight,” he said. “And so one of the things I will be doing is fighting to make sure that the executive branch abides by the law as it was issued in this state and around the nation. This will be an ongoing battle.”

The crowd cheered.

“We see tonight what I believe is a clear violation of the Constitution,” he continued. “And so clearly tonight we have to commit ourselves to the longer fight. Clearly tonight, we have to commit ourselves to the cause of our country. Clearly tonight, we have to be determined to show this world what America is all about.”

Booker told The Daily Beast that CBP didn't give him an explanation for why they wouldn’t let lawyers access detainees.

“They told me nothing, and it was unacceptable,” he said. “I believe it’s a Constitutional crisis, where the executive branch is not abiding by the law.”

A source familiar with Booker’s exchange with CBP officials told The Daily Beast that officials with the agency refused to see him face to face. Instead, Booker wrote questions on a piece of paper which he handed to police officers, and those officers gave the paper—along with a copy of Brinkema’s ruling—to CBP officials. Those CBP officials then wrote out their answers to the senator’s questions, according to the source. The source described it as a half-written, half-spoken game of telephone.

It was a surreal moment: An executive agency was defying the ruling of a federal judge, and a U.S. senator was trying—unsuccessfully—to make that agency comply.

At the end of the night, at least one traveler was still detained: a Syrian woman, who had a J-2 non-immigrant visa. Her husband is a doctor working at a hospital in D.C., and she had come to try to be with him. Her lawyer, Rob Robertson—a tall, large man with a pinkish chambray shirt, cargo pants, and a snowy white goatee—told The Daily Beast that he expected her to be taken to an ICE facility on Sunday, where an ICE agent would interview her to assess if she was truly afraid of going back to Syria. Robertson, who was representing her pro bono, said she would pass that interview process with no trouble; if she went back, she could be in serious danger.

The woman’s husband, eyes bloodshot, implored Robertson: Would she be comfortable tonight?

He said she probably would, and he was optimistic that she would be free in two weeks or less. This wasn’t Robertson’s first showdown with ICE, and won’t be his last.

“This is fun,” he said.