Secretary of State Marco Rubio said Wednesday that the US plans to “aggressively revoke” the visas of Chinese students, including those working in critical fields or with ties to the Chinese Communist Party. Experts warn the move—along with the Trump administration’s broader crackdown on international students—could drain American scientific labs of top STEM talent and upend cutting edge research in areas like artificial intelligence.

“If you were aiming to help China beat the US at AI, the first thing you would do is disrupt the flow of top talent from all around the world into the US,” says Helen Toner, director of strategy and foundational research grants at Georgetown University’s Center for Security and Emerging Technology. While it has a population only about a quarter the size of China, “the US has had a huge asymmetric advantage in attracting the cream of the global crop,” she adds.

Several close Trump allies, including Elon Musk, have argued that attracting the best engineers from around the world is essential for the US to maintain its technological dominance. But more populist figures in the White House, like top policy chief Stephen Miller, have long advocated for reducing immigration levels—seemingly at any cost.

“It is almost funny, because the White House has said that artificial intelligence is one of the top priorities for this country, but now they are trying to send the people who are doing this kind of research home,” says Zilin Ma, a PhD student from China studying AI computer interfaces at Harvard University, which has been at the center of the Trump administration’s crusade against US colleges.

Rubio’s announcement came the day after the State Department sent a cable to US embassies ordering them to temporarily suspend scheduling interviews for all prospective international students, regardless of their country of origin. The cable, which was leaked to Politico, said the pause would allow the Trump administration time to consider potentially expanding social media screening procedures for visa applicants.

The State Department declined to answer questions from WIRED about changes to its student visa policies. In an unsigned email, the department’s press office said it doesn’t comment on internal communications and noted that the US government has required visa applicants to share information about their social media accounts since 2019.

Vincent Conitzer, a computer scientist specializing in AI at Carnegie Mellon University, says America’s ability to attract top talent has been an important and longstanding asset for its domestic tech industry, which is already facing growing international competition.

“The rest of the world has for a long time envied the US for being able to attract the world’s best students,” Conitzer says. “That’s not to say that we shouldn’t screen students who want to come into this country, but they need to understand that they’ll be treated fairly, or none of them are going to come in the first place, and that will hit the US hard—the economy, the technology base, and more.”

More than 880,000 international students, mostly from India and China, were enrolled at US colleges and universities in the 2023-24 academic year. Foreigners make up particularly large shares of STEM graduate programs: Over 36 percent of STEM master’s degrees and 46 percent of STEM PhDs in the US were awarded to international students in the 2021-2022 academic year, according to data from the National Center for Education Statistics.

At some US colleges, international students make up the majority of doctoral students in departments like computer science. At the University of Chicago, for example, foreign nationals accounted for 57 percent of newly enrolled computer science PhD students last year, according to data published by the school.

Since international students often pay full tuition, they provide funding that schools can then use to expand their programs. As a result, foreign-born students are generally not taking education opportunities from Americans, but rather creating more slots overall, according to a report released earlier this month from the National Foundation for American Policy. Researchers from the nonpartisan think tank estimated that each additional PhD awarded to an international student in a STEM field is “associated with an additional PhD awarded to a domestic student.”

Restricting student visas and reducing the number of foreign nationals studying computer science “will profoundly impact the field in the United States,” says Rebecca Willett, a professor in the University of Chicago whose work focuses on the mathematical and statistical foundations of machine learning. Willett adds that the move “risks depleting a vital pipeline of skilled professionals, weakening the US workforce, and jeopardizing the nation’s position as a global leader in computing technology.”

Mehran Sahami, the chair of Stanford University’s computer science department, describes the student visa policy changes as “counterproductive.” He declined to share how many foreign students are enrolled in Stanford’s computer science program, which includes both graduate and undergraduate students, but he acknowledges that it’s “a lot.”

“They add a lot to it, and they have for decades. It’s a way to bring the best and brightest minds to the US to study, and they end up contributing to the economy afterwards,” Sahami says. But now he worries that talent will “end up going to other countries.”

The vast majority of PhD students from China and India say they intend to stay in the United States after they graduate, while the majority from some other countries, such as Switzerland and Canada, report planning to leave.

Foreign-born STEM graduates who remain in the US frequently go on to work at American universities, private tech firms, or become startup founders in Silicon Valley. Immigrants founded or co-founded nearly two-thirds of the top AI companies in the United States, according to a 2023 analysis by the National Foundation for American Policy.

William Lazonick, an economist who has extensively studied innovation and global competition, says that the US experienced an influx of foreign students studying STEM disciplines beginning in the 1980s as fields like microelectronics and biopharmaceuticals were undergoing a technological revolution.

During the same period, Lazonick says, he observed many American students choosing to enter careers in finance instead of the hard sciences. “It is my sense, from being a faculty member at both public and private universities in the United States, that foreign students pursuing STEM careers have been critical to the very existence of graduate programs in the relevant science and engineering disciplines,” Lazonick tells WIRED.

As the Trump administration works to restrict the flow of international students and slash federal research funding, governments and universities around the world have launched elaborate campaigns to court international students and US scientists, eager to take advantage of a rare opportunity to snap up American talent.

“Hong Kong is trying to attract Harvard students. The UK is setting up scholarships for students,” says Shaun Carver, executive director of International House, a student residential center at the University of California, Berkeley. “They see this as brain gain. And for us, it’s a brain drain.”