When cancer researcher Juan Tang took refuge from the US Federal Bureau of Investigation (FBI) at the Chinese consulate in San Francisco in July, she drew national attention. Days later, the FBI arrested Tang — a Chinese national who was on a months-long research assignment in the United States — on charges of concealing her role as a Chinese military officer from the US government. Tang has since entered a not-guilty plea and, as of early September, is in custody in California, though her team of attorneys is arguing for her to be released while she awaits a jury trial.
Around the time of her arrest, the US authorities announced the arrests of a handful of other Chinese scientists for allegedly hiding ties they had to China’s military on visa applications. Scholars of US–China policy say that the arrests mark a new front in the United States’ battle against foreign interference in its universities and labs, in which government officials are increasingly scrutinizing researchers’ links to China’s People’s Liberation Army (PLA).
Scientists with ties to the Chinese military have been visiting the United States for years, says Brad Farnsworth, vice-president of the American Council on Education in Washington DC — but only now are officials “really looking very carefully at the background of the people who come here, particularly from China”.
Exactly how the FBI and the US Department of Justice (DoJ) are focusing their investigations remains unclear, but literature analyses — including one from Nature — are beginning to illuminate how widespread links are between US researchers and Chinese scientists with potential military ties. The lack of concrete information from US authorities has triggered concerns that some scientists might be unfairly accused of espionage.
Many of the top hospitals in China, for example, are affiliated with the military, says Mary Gallagher, a political scientist who studies US–China relations at the University of Michigan in Ann Arbor. “And so by default, if you’re a doctor at one of those hospitals, you’re going to have an affiliation with the Chinese military.” That affiliation doesn’t automatically mean that if you’re collaborating with a US researcher you’re engaging in espionage, she says.
A new chapter
The arrests come as escalating tensions between the United States and China over the past few years have increasingly spilled over into research. In 2018, US President Donald Trump’s administration announced the China Initiative, aimed at stopping China from stealing intellectual property and technologies from US companies and research labs. But until recently, actions by the US enforcement agencies had mostly involved taking into custody scientists who failed to declare foreign research money to US funding agencies who also supported them.
The US government’s recent focus on researchers’ links to the PLA has arisen alongside Chinese President Xi Jinping’s ‘military–civil fusion’ strategy, in which university research and corporate intellectual property are being tapped for military use. The strategy has also prompted Japan and Australia to take steps to prevent China from co-opting technology and intellectual property developed in international academic collaborations. And in May, the Trump administration issued an order that would reject visa applications from researchers and students from some military-linked Chinese institutions, barring those people from entering the United States.
The arrests announced in July all involved accusations of visa fraud, according to officials at the DoJ and the FBI.
Tang had been a visiting researcher at the Department of Radiation Oncology at the University of California, Davis, since January. DoJ officials claim Tang denied serving in the military on her visa application — but that she is a “uniformed officer” in the PLA Air Force, a claim based in part on photographs of her in a military uniform that they submitted alongside the charges. The agency also claimed that the other researchers whose arrests were announced in July — Xin Wang, a postdoctoral researcher studying obesity and metabolism at the University of California San Francisco; Chen Song, a neurobiologist visiting Stanford University; and Kaikai Zhao, a graduate student researching machine learning and artificial intelligence at Indiana University Bloomington — had past or current appointments in the Chinese military that they misrepresented on their visa applications.
Those cases follow the charge this January of Yanqing Ye, a physics researcher at Boston University in Massachusetts, who the United States also claimed hid an active appointment in the PLA.
Like Tang, Wang has entered a not-guilty plea. Malcom Segal, an attorney in Sacramento, California, who represents Tang, says that “her case has no relationship whatsoever with any of the other cases charged by the government”. Attorneys for Wang and Song declined to comment to Nature; Zhao’s attorney did not respond to requests for comment. All four cases are ongoing. Nature was unable to contact Ye. The FBI believes that Ye is now in China; a Boston University spokesperson said that Ye is not currently affiliated with the university.
The extent to which US research is actually being funnelled to the Chinese military, and how to block it meaningfully and fairly if it is, remain unclear, say experts — as do the parameters the United States is now using to label foreign scientists and collaborations a threat.
According to court filings, Zhao was working on military radar technology. But otherwise, the five scientists’ fields of research alone — neurobiology, cell biology, medicine, physics, and machine learning — would not raise alarm from a national security perspective, experts say.
Federal agents have not been transparent about what kind of US-China collaborations they view as risky. Glenn Tiffert, a research fellow at the conservative Hoover Institution, a public policy think tank at Stanford University in California, suspects that there are many other cases that the government deems problematic from a national security perspective.
A tangled web
To estimate the scope of the US government’s concerns, in July, Tiffert and other colleagues at Hoover studied US links to seven universities in China, known as the ‘Seven Sons’, that were founded by or assisted the military before becoming civilian centres of higher education.
In July, the team released an analysis of Chinese- and English-language academic studies from 2013–19 that were listed in a major Chinese science and technology publishing database. It found 254 that were coauthored by at least one scientist from a Seven Sons university and one from a US university; the papers involved a total of 115 US universities.
Tiffert emphasizes that none of the collaborations his team found was illegal, and hopes the study will encourage US research universities to re-think which partnerships could be considered problematic.
But an analysis by Nature using the Dimensions database from Digital Science, based in London, suggests that links between Chinese and US scientists are more prevalent than the Hoover report suggested. Analysing a larger selection of research papers — over 100 million of them — in this worldwide database, Nature found more than 12,000 publications from 2015–19 co-authored by scientists in the United States and at one of the Seven Sons. Among those, 499 authors had a dual affiliation with a US institution and a Seven Sons university and were listed on papers declaring grant funding from the NIH or the US National Science Foundation (NSF).
The Nature analysis “confirms that the research ties between China and the US are very deep”, says Farnsworth. Tiffert says he’s not surprised by the results because the Dimensions database that Nature used is bigger and more detailed.
But separating true threats from ordinary collaborations could be a challenge, some experts say. It has not been unusual for Chinese researchers with appointments in the military to visit the United States and work on non-classified projects, says Denis Simon, senior adviser to the president at Duke University in Durham, North Carolina. Simon led the Duke Kunshan University in China as vice-chancellor until July this year. “To assume a comprehensive conspiracy is too far from the reality,” he says.
As military–civil fusion emerges as a flash point for US officials, some worry that future federal actions could be disruptive to universities and researchers. The Trump administration announcement in May barring scientists and students affiliated with military-linked Chinese institutions from coming to the United States was criticized as too broad. The order is expected to affect up to 5,000 potential new students from China, according to Farnsworth. One-third of foreign students studying in the United States — about 370,000 students as of 2019 — are from China.
In general, universities do not have rules that bar scientists with affiliations to the foreign military from working the university’s researchers. But in the absence of nuanced federal guidelines, institutions may well be forced to take a fresh look at these collaborations.
“There is no longer any status quo to go back to,” says Farnsworth.