First, I want to correct the Donald when he says that "NAFTA was the worst trade agreement ever". A sentiment echoed by people who don't know anything and really enjoy not knowing anything...
This is U.S. manufacturing employment:
This is the U.S. trade deficit. The jobs didn't go South, they went East, but the Idiocracy is deaf, dumb, and BLIND:
More importantly, "how did this happen?"
Globalization was always only about one thing: Corporate profit. It was the arbitrage of the developed world lifestyle in exchange for a Third World lifestyle, all to bolster quarterly profit prior to global economic collapse. It was amplified short-term profit margins in exchange for long-term sustainable revenue.
Corporate profits baselined to U.S. GDP:
Milton Friedman: "Never let a good crisis go to waste"