If the US imposes this charge, they will go somewhere else. Europe, maybe. China, maybe. We won't get the immediate benefit of their work like we do now. This will kill some graduate programs and constrain a lot of others. It is hard to see any positive benefits from this move.

If I were China, I'd move on this aggressively. If I were any country with a strong interest in STEM, I'd do the same. In fact, just the mention of this action should spur a somewhat aggressive response.