Students from China (and many other countries) are required to renew their visas annually, a process which is already quite nerve-wracking for many. PhDs in particular can take anywhere from 4 to 8 years to complete, meaning 4-8 chances for your studies to be interrupted with the only option to return home while the visa renewal stalls. This article explicitly calls out the fact that renewals seem to have been gettin…
Was American science declining in the 1960s when almost no Chinese students were in American universities? Could there also be extremely smart people in Africa that might now find a place in American universities? Are there Americans that might now find a place in American Universities? I am not saying anything about visa policies, but suggesting that limiting Chinese students will hurt American science is a pretty n…
The lack of infrastructure, support and adequate living conditions is all that severely limits them from reaching their potential and they know this, which is why they climb the Everest of bureaucratic hurdles to get to a place like the US. China is a unique case because it has become wealthy (enough) very quickly and critically also has a very large population, which statistically increases the chances of very intelligent people appearing given the right conditions; if 1% of a billion population is very intelligent that's 10 million people in real terms.
I don't think the US has the dominance it did in science like it did in the 60s, when Europe and Japan were still recovering from war and China was still poor. I think the loss of a large number of Chinese students would certainly have an affect on the US's development in science today.