A little while ago, VDARE.com's Patrick Cleburne  posted a blog entry  hinging on a refreshing and enlightened remark from a former Silicon Valley executive to the effect that U.S. universities should be denied access to foreign (graduate) students, thus forcing them to return to their founding purpose, educating our own students.
That exec's recommendation was anticipated nearly 20 years ago by Caltech physicist and former vice-provost David Goodstein . His article Scientific PhD Problems (The American Scholar [Phi Beta Kappa's journal], Spring, 1993, see online version ) was principally about the saturation of the job market for PhDs after its breakneck growth through the late 1950s, 1960s, and early 1970s (i.e. the number of PhDs inevitably increases to absorb all the research funding).
As a result, wrote Goodstein, some of the more observant U.S.-born students were catching on to their declining prospects for careers in scientific research and, thus, diverting themselves into other directions. (Goodstein doesn't mention research-oriented engineering students, but I think the phenomenon is the same for them; see the example linked below.) So the university departments that do research, which had generally built themselves for a steady flow of grad students, started encouraging applications from abroad.
Indeed, when I was a grad student in the astronomy departments at Caltech and the University of Chicago in the early- to mid-1970s, I recall only one (possibly) foreign student in the former and none in the latter. But today, cast your eyes on the graduate-student roster  for Caltech's Department of Electrical Engineering to see the phenomenon Goodstein wrote about at the end of his article:
"The American taxpayer (both state and federal) is supporting extremely expensive research universities whose main educational purpose is to train students from abroad. When these students finish their educations, they either stay here, taking relatively high-paying jobs that could have gone to Americans, or they go home, taking our knowledge and technology with them…Congress and the public [don't] seem yet to have noticed that, while largely ignoring our own students, we are putting our money and our best talent into training our economic competitors. Just wait until this one hits the fan."
But nineteen years later, few Americans and probably zero congressman and senators have caught on to what Goodstein was getting at. i.e. "This one" still hasn't hit the fan!