MAGA thinks it can tamp the flow of foreign imports and force a domestic jobs and manufacturing renaissance when a) factories don't need many people anymore because of automation, b) we can't source a lot of things locally, and c) it would take decades for companies to build that capacity -- which they won't as long as it's still cheaper to use international supply chains. You would have to isolate the US completely, at which time the economy would crash and no one would build anything.