In an April speech in New York, FBI director Christopher Wray described the reason for the scrutiny of ethnic Chinese scientists. “China has pioneered a societal approach to stealing innovation in any way it can from a wide array of busi­ness­es, universities and organisations,” he told the Council on Foreign Relations. Every­one’s in on it, Wray said: China’s intelligence services; its state-owned and what he called “ostensibly” private enter­prises; and the 130,000 Chinese graduate students and researchers who work and study in the US every year. “Put plainly, China seems determined to steal its way up the economic ladder at our expense.”

This has been going since long before the Trump administration, probably all the way back to the Clinton one.