If you restrict the pool of applicants, the quality of the student body will go down. That's basically a law of nature.
Schools aren't accepting foreign students because they're cheaper. They actually have greater apprehension about foreign students, because their language skills might be lacking, and because the American professors judging the applications might not personally know the foreign professors writing the recommendation letters.
Science is largely done by graduate students and postdocs. Professors are busy writing grants, teaching classes, advising students and sitting on committees. Their role in science is largely managerial, and in providing overall vision. All the grunt work and detail gets done by people below them. My point is that having smart and capable students is critical.
If you go into a top STEM department in the US, you'll probably see that a large majority of students are foreigners. If you were to exclude them, you could replace them with Americans, but those Americans would, on average, have lower grades, lower test scores and less previous research experience. Their work would not be as good, and the productivity of the department would fall.
The excluded students would instead go to top universities in other countries. Those universities would begin doing better research as a result. My prediction is that within a decade, you would see Harvard, MIT, Princeton, Stanford, UC Berkeley et al. fall off the top of the rankings, replaced by the top universities in Europe, one or two universities in Canada, and perhaps a few Asian universities.
Schools aren't accepting foreign students because they're cheaper. They actually have greater apprehension about foreign students, because their language skills might be lacking, and because the American professors judging the applications might not personally know the foreign professors writing the recommendation letters.
Science is largely done by graduate students and postdocs. Professors are busy writing grants, teaching classes, advising students and sitting on committees. Their role in science is largely managerial, and in providing overall vision. All the grunt work and detail gets done by people below them. My point is that having smart and capable students is critical.
If you go into a top STEM department in the US, you'll probably see that a large majority of students are foreigners. If you were to exclude them, you could replace them with Americans, but those Americans would, on average, have lower grades, lower test scores and less previous research experience. Their work would not be as good, and the productivity of the department would fall.
The excluded students would instead go to top universities in other countries. Those universities would begin doing better research as a result. My prediction is that within a decade, you would see Harvard, MIT, Princeton, Stanford, UC Berkeley et al. fall off the top of the rankings, replaced by the top universities in Europe, one or two universities in Canada, and perhaps a few Asian universities.