NEW YORK (AP) — It had been a few years since attorney Roman Zelichenko left immigration law for a career in finance, and longer still since he pulled an all-nighter.
But after President Donald Trump issued his immigration order, Zelichenko spent 21 straight hours at what swiftly became one of the nation's most closely watched immigration law centers — a diner at John F. Kennedy Airport where volunteer lawyers, translators and others tried to find and free people detained under the new rules.
Alerted by law school friends, Zelichenko joined the effort because it resonated personally: He emigrated from Ukraine as a child.
"We all have different personal connections," he said Monday as he worked on the project's social media postings. But "we're here as professionals, and our agenda is to uphold the rule of law."
As Friday's presidential order reverberated around the world, dozens of attorneys descended on JFK to advocate for people suddenly stuck in a legal limbo that the lawyers argue is unjust and unlawful.
Trump temporarily banned refugees and citizens from seven Muslim-majority countries from traveling to the U.S. Throughout the weekend that followed, travelers were held for questioning, confusion spread across the air-travel system and protesters marched against the measure.
Mobilized by email and word of mouth, the legal effort known on Twitter as "NoBanJFK" is one of several at major U.S. airports. Lawyers filed roughly two dozen lawsuits on behalf of detainees in several states and won several federal court rulings that, at least temporarily, blocked the government from removing people who arrived with valid visas.
At JFK, where lawyers helped win the first of the rulings Saturday night, the round-the-clock work began with attorneys typing on laptops on the airport floor. Now they sit at a cluster of cafeteria tables, and law students have toiled alongside seasoned litigators.
The volunteers take hotline calls on cellphones. Signs in multiple languages offer help.
More than 650 attorneys have volunteered for the project, which participants feel has done their profession proud.
"I think lawyers get a bad rap, and sometimes it's deserved. But most of us went to law school to help people," said Melissa Trent, a civil rights lawyer who left a training session to spend over 24 hours at the airport over the weekend.
"We believe in this country, its laws and the Constitution ... and when we see those values challenged, we show up."
The lawyers say Trump's order violates constitutional protections against religious discrimination, among other principles and federal laws.
Trump casts the measure as a safeguard against violent Islamic extremism. The order temporarily blocks immigrants and visitors from Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen. It does not include all countries with ties to terrorism affecting the U.S., nor does it address the threat of homegrown militants.
Legal experts are divided as to how federal courts will ultimately view Trump's action.
Whatever the final outcome, the airport attorneys and groups working with them have demonstrated a spontaneous form of legal rapid response to the new administration's policies. Meanwhile, Democratic state attorneys general are mounting broader challenges.
Roughly 400 attorneys have signed up to volunteer at Chicago's O'Hare Airport, taking six-hour shifts from 6 a.m. to midnight.
On Tuesday, some held signs — "Do you need an attorney?" ''Was anyone on your flight detained?" — in arrival areas. Supporters donated office supplies, coffee and doughnuts.
At Dallas-Fort Worth International Airport, reports of detained travelers were still coming in Tuesday to volunteer lawyers who organized an airport hotel "war room" and set up tables outside the customs area, attorneys Peter Schulte and Paul Wingo said.
A legal team also set up in the international arrival area at San Francisco's main airport. And at Washington Dulles Airport, about 100 attorneys gathered on Sunday alone.
"I was born here in order to help people who can't help themselves," said Mariam Masumi, who is Muslim, an immigration lawyer and the daughter of Afghan immigrants. She skipped a funeral to lend her skills at the airport.
With no information coming from the government on who is being held, legal volunteers glean what they can from arriving passengers and from detainees' relatives or friends.
"These were families that were torn apart who had done nothing wrong," says Russell Kornblith, an employment-discrimination lawyer who joined the JFK effort Saturday with his fiancee, Elizabeth Rosen, a corporate litigator.
One family Kornblith met was waiting for a 68-year-old Yemeni woman with diabetes who had a visa to stay with her son, a U.S. citizen, lawyers and relatives said. She was ultimately released after Saturday night's court order.
Carolyn Lipp isn't even a lawyer yet, but she got a new sense of the profession's potential at JFK, helping with the work that won the New York court order.
"It's definitely why I came to law school, to do something like this," said Lipp, a Yale Law School student who got involved through the school's Worker and Immigrant Rights Advocacy Clinic. "To make a difference."
Associated Press writers William Mathis in New York; Ben Nuckols in Chantilly, Virginia; Olga Rodriguez in San Francisco; Sophia Tareen in Chicago and David Warren in Dallas contributed to this report.