Assuming that its accomplishments include moving manufacturing back into the US and securing the border, what good could come of a populist movement? The interests of the American labor aristocracy would just be consolidated with Imperialism to an even greater extent, and any conflict against China would see no resistance from organized labor because of the incestuous relation of the MIC and organized labor. Any anti-war movement would have no power at all, there would be no positive argument for stopping the conflict when it keeps everyone employed as contrast to the current state of unemployment and precarious work.
Potential benefits include the cessation of the export of capital, less capacity for the US to project power across the world, and less state repression of anti-imperialist movements. But I can't help but think that if the US pulled its production out of Asia, South America, Africa, and the Pacific, it would redo Gladio/Bloodstone to prop up fascists to hold down anti-imperialist movements, or create a dozen Israels to keep a way to quickly kill nascent revolutions. Am I wrong?
Isolationism.
Trump pulls out of NATO
Sanctions everyone to ttry isolated them, with the effect of isolating him
He never seriously meant this, it was a hard sales tactic.
Actually possible but I think that if it's the kind of populist movement that I consider to be most likely to have traction in the US, the treat hogs would legitimately do dozens of terrorist attacks to get treats flowing again in this case.