India, June 3 -- The US announced last week it is revoking the visas of hundreds of Chinese nationals studying and researching in high-value science and engineering fields. This sweeping decision by the Trump administration represents a major escalation in tensions with Beijing and is aimed at curbing what it describes as the Chinese Communist Party's efforts to steal US intellectual property through academic institutions. The decision has triggered protests from American universities and reignited debates about immigration, openness, and national security. But it also marks a turning point. For the first time in decades, the US is limiting academic access on national security grounds-a move that, while controversial, is not without justification. As someone who has taught at Duke, Stanford, Harvard, and Carnegie Mellon, I have long believed in the power of openness. The US has led in innovation precisely because it has welcomed the world's brightest minds. Over the last four decades, its top universities have drawn extraordinary talent from countries like China and India. These students have earned advanced degrees, contributed to major breakthroughs, launched start-ups, and helped build the US tech economy. Many of my students from China and India were among the most diligent, creative, and capable I have taught. At Carnegie Mellon's Silicon Valley campus, where I taught a course on exponential innovation - covering Artificial Intelligence (AI), robotics, cybersecurity, and synthetic biology - more than half of the class was Chinese. Most of them were outstanding and will no doubt go on to do great things. But not all Chinese students come to the US solely to learn. In 2005, I was teaching a course and conducting research at Duke University comparing engineering education in the US, China, and India. One Chinese student stood out - not for academic excellence, but for disinterest. When I asked him why he had enrolled, he told me plainly: His father was in the Chinese military, and he had been sent - on a government scholarship - to study, make contacts, and report back. Years later, a European institute contacted me to verify a recommendation letter I had supposedly written for him. I had written no such letter. It had been forged - presumably to help him gain access to sensitive research. In other cases, I met Chinese students who openly said they were on Chinese military-sponsored programmes. They worked hard to align themselves with professors conducting cutting-edge research in photonics, quantum devices, and advanced materials-fields with clear military applications. To be clear, this is not the norm. I estimate that only a small, single-digit percentage of Chinese students are sent abroad with such strategic intentions. But even a small number, when operating in critical research environments, can have an outsized impact. What troubles me more is how US universities often look the other way. At every institution where I taught, professors routinely received invitations from Chinese universities to collaborate or attend conferences - with business-class airfare, honorariums, and perks for spouses. Visiting researchers from Chinese State-linked institutions were welcomed with little scrutiny. Everyone seemed to treat it as business as usual. I myself received dozens of such invitations. I declined nearly all of them, except for a research trip to Hong Kong organised by the New York Academy of Sciences which paid $5,000. I also hosted Chinese scholars at Stanford and CMU, receiving modest stipends. At the time, my colleagues assured me this was routine and did not require disclosure. But in hindsight, I see how easily these engagements can blur into influence operations, especially in the absence of transparency. Meanwhile, America's own immigration system continues to undermine its competitiveness. Because it is so difficult for foreign students to stay after graduation, nearly all of my Chinese students returned home. They took with them the knowledge, networks, and experience they gained in the US - and many will now use that to advance China's strategic goals. If the class had been made up of 80% American citizens and 20% foreign students committed to contributing to the US, that would have felt balanced. But what I witnessed was lopsided. I increasingly worried that I might be helping train technologists who would later compete with democratic countries. That was one of the reasons I chose to step away from teaching. This doesn't warrant blanket bans. The US must remain open to the world's talent, but it also must be smart. Visa and research screening should include affiliations, risk, and research domains. If a student or researcher has ties to the Chinese military or a State-backed research initiative, they should not be allowed into the country or granted access to sensitive technologies or federally funded labs. Universities must also be held accountable. They should be required to fully disclose all foreign funding sources. Faculty should not be permitted to accept undisclosed compensation or enter into informal partnerships with institutions tied to adversarial governments. Sensitive research, particularly in dual-use technologies, must be governed by stronger security protocols - on par with those used by government contractors and national laboratories. China is not just another academic peer. It is a surveillance State, a strategic rival, and an authoritarian regime with a declared ambition to dominate critical technologies. It does not separate research from national interest, unlike democracies such as the US and India, which must now work together to protect the integrity of their institutions....