There may be arguments on the basis of overpopulation against so much immigration, but that seems a global rather than national problem, so in general, I welcome good foreign grad students and profs. We're happy to use the natural resources of the rest of the planet, so why not the intellectual resources. That's much of the reason for the US to have thrived after WWII, for example.

One of my biggest gripes with the current administration and its supporters in the us vs them attitude and the concept of the US as insulated from the developments in the rest of the world.