Back in 1972, John Lennon hired Leon Wildes, an immigration attorney who had no idea who he was.
Wildes' son, Michael, remembers his father coming home to tell his mother about their first meeting.
"And he said, 'A singer by the name of Jack Lemon and his wife Yoko Moto,' " Michael recalls. "My mom looked at him like he wasn't well. 'Are you talking about the Beatles and John Lennon?' My father said, 'Yeah!' "
Over the next five years, Lennon and Ono were often caught on camera outside immigration court in New York City — as well as on late-night talk shows such as NBC's The Tomorrow Show With Tom Snyder.
"What is your status in the country right now?" Snyder asked Lennon during a show taping in 1975.
"That's why Leon's here," Lennon answers. He glances over at Leon Wildes sitting across from him on a dark TV set. "What, what am I, Leon?"
"Well, John was charged with being deportable in the U.S. for being an overstay," says Wildes, who has written a new book about Lennon's deportation case called John Lennon vs. The U.S.A.
In other words, Lennon was on a tourist visa that expired while he was helping his wife, Yoko Ono, with a custody battle over her daughter from a previous marriage.
So Wildes got that visa extended. But immigration officials gave them only just over month before Lennon would have to leave. Later, Wildes put in an application for a green card, which was denied.
But Lennon still wanted to stay in America.
"I like to be here because this is where the music came from," Lennon said. "This is what influenced my whole life and got me where I am today."
Wildes appealed the denial.
But FBI files show that the Nixon administration wanted Lennon, along with his anti-war activism and influence over young voters, out of the country.
So Wildes started digging for another route.
"I always had a feeling that the government must have a program to exercise some discretion," Wildes said.
Asked why he had that feeling, Wildes said it was "because there were rumors of certain guys who were — had critical criminal backgrounds and bad immigration histories and seemed to be still around."
Those guys probably benefited from what's now known as "prosecutorial discretion." It's based mainly on the premise that the federal government doesn't have enough resources to deport all of the immigrants living in the U.S. illegally.
Under federal law, immigration officials can choose to prioritize certain deportation cases while holding off on other ones for humanitarian or political reasons.
The problem at the time was that Wildes didn't have proof that this kind of program existed until he filed a Freedom of Information Act request.
"When the box came into my office, there was jubilation!" Wildes said. "Unbelievable feeling that I had succeeded."
In the end, Lennon received a green card, which allowed him to stay in the U.S. But those files led U.S. immigration officials to publicize a secret policy.
"Before the work of Mr. Wildes, deferred action was a complete mystery because there wasn't even a guideline for attorneys and noncitizens," says Shoba Sivaprasad Wadhia, who teaches immigration law at Penn State University and wrote Beyond Deportation: The Role of Prosecutorial Discretion in Immigration Cases.
The files showed that for decades, the government had shielded some immigrants living in the U.S. illegally from deportation because of their sympathetic cases. The Obama administration used that policy to create the original Deferred Action for Childhood Arrivals program, or DACA.
"Eligible individuals who do not present a risk to national security or public safety will be able to request temporary relief from deportation proceedings and apply for work authorization," said President Obama in a 2012 announcement.
An expansion of the program, as well as the creation of a similar program called Deferred Action for Parents of Americans and Lawful Permanent Residents, or DAPA, is currently on hold because of legal challenges.
But today, the original DACA program covers more than 700,000 young people brought to the U.S. as children — all in part because of that immigrant from Liverpool.