Updated on Sept. 24 at 8:45 a.m. ET.
Aaron, a Beijing native, spent the last seven years in the United States, first as a high school student and now as a rising college senior in sociology — until he received an email from the U.S. State Department earlier this month.
"I opened it and it basically just said, because of some new information that we recently received, your visa has been revoked," Aaron remembers. He reached out to two lawyers with the help of his American university, who gave him grim news: "You're probably not going to get your visa ever again."
NPR is not using Aaron's full name because he fears he may face discrimination and further suspicion in the U.S.
Aaron was one of more than a thousand Chinese students and researchers who lost their visas Sept. 9 because the State Department said they were "high risk" — meaning they were alleged to have hidden their ties to China's military when applying for student visas.
The visa revocations come after a May executive order in which President Trump said the U.S. would cancel or deny student visas for anyone with direct connections to China's military.
It is the most dramatic step yet the U.S. has taken to counter what it says is a concerted Chinese espionage effort leveraging nontraditional sources of information collection, namely students, to steal industrial secrets and technology from American universities and firms.
Last year, the U.S. began curtailing visas for Chinese graduate students studying in some cutting-edge science and engineering fields and stepped up screening measures for visa applicants, delaying applications by months.
"These researchers are told by the Chinese government when they fill out their applications not to disclose their affiliations with the [People's Liberation Army]," said John Demers, U.S. assistant attorney general for national security, speaking at a conference in September. "These [students] are really parts of a program on the part of the Chinese government."
Searching for spies
The FBI has launched a wide-ranging "China Initiative" to harness bureau resources to combat alleged economic espionage. FBI Director Christopher Wray says the bureau has more than 2,000 active counter-espionage cases related to China.
The National Institutes of Health, a major federal funding body for medical research, said it has investigated more than 180 scientists for not reporting their foreign-state funding. Fifty-four researchers in the U.S. have already resigned or been fired from their positions over related issues.
This spring, U.S. Customs and Border Protection ramped up airport screenings of departing Chinese researchers as thousands left the U.S. during the coronavirus pandemic.
"It's fair to say that throughout the entire process, the agents have assumed that you are a spy," one Chinese researcher told NPR. "All we could do is to defend our innocence."
He said he was stopped and questioned at Los Angeles International Airport about his research when leaving for China. He believes he was targeted because of his Chinese state scholarship to study mechanical engineering in the U.S. He asked to remain anonymous to avoid further suspicion.
The researcher said two U.S. agents searched his electronic files and even checked his pen caps for their contents. He was allowed to board his plane after explaining the nature of a large amount of data sent to him by an American colleague via email.
The U.S. Justice Department has prosecuted dozens of academics and students, mostly from China, accused of not disclosing Chinese state funding or Chinese military ties in the past two years.
Just this July, the DOJ accused four Chinese researchers in the U.S. of concealing their work for the Chinese military when applying for American visas. One temporarily took refuge in the Chinese Consulate in San Francisco, before being arrested after leaving the building for a medical appointment.
Caught between two antagonistic governments
Aaron was confused about how he fit into all of this. He had spent high school and college in the U.S. What military links could he have?
Racking his brain, Aaron realized his Chinese identification documents listed his permanent address as the campus of a Chinese defense university.
"My grandma and my grandfather were professors there," he said. "so I have been living with them when I was in kindergarten and elementary school, and I went to a kindergarten and elementary school affiliated to the university. That was the only connection I have with the university."
Aaron's predicament is common. Many of China's best elementary, middle and high schools are affiliated with state universities — but their students often have no link to the university itself.
Those who study the interplay of Chinese and U.S. higher education say a tiny subset of the more than 360,000 Chinese students in the U.S. may pose a threat to national security. They say revoking visas could be catastrophic for America's efforts to attract Chinese research talent.
Matt Sheehan, a fellow at the Paulson Institute, which studies the U.S.-China relationship, has found that nearly a third of the most advanced work in artificial intelligence in the U.S. is done by Chinese nationals.
"There's no precise way to measure the national security costs versus the benefits of Chinese researchers in our ecosystem," Sheehan says. "But given that they're contributing to about one-third of the top AI research output, it's tough to imagine that that is outweighed by the industrial espionage cases that we've seen to date."
Should the U.S. continue to revoke or restrict visas, Chinese researchers will almost certainly go elsewhere, Sheehan says.
"I think our policymakers have kind of been lulled into believing that the way that we treat immigrants and the way that we treat incoming researchers doesn't matter because they'll come here no matter what," says Sheehan. "But ...people are no longer forced to study in the U.S. if they want to stay at the forefront.
Aaron's story has sort of a happy ending. About two weeks after his visa was revoked, the State Dept. told Aaron it made a mistake. It reinstated his visa and said he could return to the U.S. once coronavirus restrictions eased. But he is now wary of having anything to do with the U.S.
"I am not staying in the States because it seems like they can just take my visa at any moment, and then they can kick me out of the country. I really don't want to have to deal with that again," he says
Instead, Aaron says he's now aiming to work in the European Union. If they don't want him there, there is always the option of returning to China.