[rjbwork]

Targeted tariffs in combination with robust industrial, economic, and monetary policy can be effective in incentivizing certain types of production to remain in, grow in, or return to a country.

Blanket tariffs on entire countries or indeed the entire world amounts to a massive tax increase on your entire populace unless you can somehow start producing everything yourself immediately.

There is an argument that it's primarily being used as a cudgel to give the US an advantageous starting position in trade negotiations, but that seems to be a post-hoc explanation/justification.