Not fully fleshed out thought: Trump's proposal to "Buy American, Hire American" sounds good on some level. It's yet another simple answer to a complex problem, and I see how it's appealing. Leaving aside the questions of the global economy and trade wars with the rest of the world, though, there's one simple thing that I think will prevent it from being fully realized: Americans love cheap crap. I'm sure if you polled people, 90% of them will say "I try to buy American products whenever possible," and a few of them may actually do that, but really? People go to Target and Walmart and buy the cheapest thing on the shelf that fills their need without giving a second thought to where it was manufactured.
Hell, there's a whole region in China where the whole economy is about supplying western dollar stores. I'm sure some people in this country shop at dollar stores because they have to, but some do it because they like their stuff to be cheap. So if we really did start buying everything American, prices would go up and then people would be pissed about that instead.