Donald Trump's brain drain
This is one of the most insidious ways Trump is crippling the United States. With the stricter immigration policies and the perception, right or wrong, of a more xenophobic administration, a lot of highly skilled foreign workers and academics that otherwise would come to the US are now staying at home or going elsewhere. Many Trump supporters support this because they think saving a few thousand of those jobs for American workers in the short term is worth massive losses in America's overall economic / innovative abilities on both an absolute and relative level.
Granted, Trump has expressed his intentions to make immigration more meritocratic, but it's unclear if he will actually structure it in such a way that the net amount of high-skilled workers increases.
But who needs any of that when you're bringing coal back, amirite?