Now convince Trump's supporters that this is true.

Right, but a bit vacuous: Trump personally decides what (categories of) goods get tariffs, and which importers and exporters. I personally never want to hear conservatives talk about "distorting the market" or similar topics. Either they were lying about faith in markets pre-Trump, or they're lying about how good a mercantilist system is today. And, no, "we've gotten new data" is not an excuse. Conservatives were standing athwart history and yelling "Stop!" They had these sacred, immutable principles that "new data" did not effect.