I would add the admittance of China to the WTO as another proximate cause. And one which probably had more of a material effect than NAFTA; but, NAFTA had already become a GOP talking point and it just stuck. China’s entry to the WTO was also moved over the finish line by Bush II, though most of the ground work was laid by Clinton. So, it wouldn’t have had the same clean narrative as NAFTA. US Employment in manufacturing went into freefall in late 2000 and early 2001. This was also during a recession, so that is intermixed with the effects of those changes in international trade. But, even as the recession receded and the US entered an economic boom, leading up to the 2008 crash, manufacturing employment in the US either held steady or decreased slightly. It’s unsurprising that the same period saw a lot of offshoring of manufacturing to China. And this was also the period of Neoliberal economists pushing “comparative advantage” and how the US losing all those manufacturing jobs was a good thing.
So it’s not surprising then that they get bitter, they cling to guns or religion or antipathy to people who aren’t like them or anti-immigrant sentiment or anti-trade sentiment as a way to explain their frustrations.
– Barack Obama, 2008