Scientific truth does not respect international borders, but access to it can be denied within borders.
There are students right now about to receive their undergraduate degrees in this country. Many of them will not be funded for research positions.
The best of them may be tempted to go overseas. Some of them surely will. (One of my son's ex-girlfriends, a Mexican American, is now in Geneva.)
Research programs now underway will lose, have lost, funding, grants being rejected. The NIH cannot function under brain worm boy.
Science is not a spigot you turn off and turn on again at will. In my experience, it requires continuity.
This increasingly has the feel of 1930's Germany, which of course, ultimately led to the scientific preeminence of the United States, at that time, a beacon of freedom. The best scientists in Germany left.
When David Hilbert died in 1943, only 13 scientists were left to go to his funeral.
I'm noting currently world scientific leadership heading to China, at least in the journals I monitor.
China may not be a "free" country, although my son, who spent last summer there said it didn't feel oppressive, but at least they respect and do science.
I advise high school students to study Chinese. They may well need it.