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?
One important aspect of eating their own tail is the overuse of sanctions in the past two decades. What was once a targeted siege war on particular enemies of the US has become a broad and still growing tactic to replace military force. At this point over a third of all nations have some kind of sanctions on their people, properties, or organizations. We're at the point where sanctions are now isolating the metropoles from foreign markets, and meanwhile sanctioned countries are working together to avoid trade in USD.
They absolutely won't lift the sanctions, and in fact are only going to increase them, but in so doing they're dooming the purchasing power of their own basket of currencies.