Some of them stayed. Not all of them were allowed to.

By 1948 thousands of Chinese students and scholars were already studying in the United States when civil war made return home impossible for many of them. The Displaced Persons Act of 1948 granted permanent resident status to 3,465 of them, stranded not by persecution abroad but by the collapse of the government that had sent them.

The Refugee Relief Act of 1953 extended that relief to 2,777 more. Together the two statutes describe a policy choice made twice in five years: rather than send trained scientists, engineers and physicians back into a country in the middle of a civil war, the United States let them finish what they had come to do.

Two of them are easy to check by name. Tsung-Dao Lee and Chen-Ning Yang arrived as graduate students at the University of Chicago in the mid-1940s, stayed, became American citizens, and shared the 1957 Nobel Prize in Physics for their work on parity violation. Their case shows what the policy was for.

Not every case ended that way. Tsien Hsue-shen, a founding figure at Caltech's Jet Propulsion Laboratory who held US defense clearances, was deported to China in 1955 during the same decade this policy was meant to protect people like him, a reminder that the era's welcome had limits it did not always honor.

Sources: the Displaced Persons Act of 1948; the Refugee Relief Act of 1953 (Pub. L. 83-203). Lee and Yang's arrival dates and 1957 Nobel Prize are independently well documented and not drawn from the two acts above. Tsien Hsue-shen's 1955 deportation is included as a documented limit on this policy, not as a case it covers.