This makes absolutely no sense as a policy.
First, there have been huge numbers of manufacturing jobs in the U.S. that Americans simply didn’t want to do, so adding more manufacturing jobs they also don’t want to do isn’t going to help the economy. It’s the proverbial, “Americans don’t want to screw tiny screws into iPhones.” situation.
Second, for there to be any prayer of the tariffs working to boost local production (whether staffed or automated), they both cannot be capricious nor can they be applied to the goods and services necessary to acquire and deploy in service of increasing that productive capacity. If the tariffs can be waved around randomly like a threat of grounding a child, then they work only as an instrument of short-term extortion, not as a mechanism to expand an economic base. If the goods and services required for expansion are tariffed, then there’s a giant margin and time-to-ROI disincentive to make the investment as well.
Third, there is absolutely no good reason to apply tariffs to goods and services for which you have no plausible domestic substitute. There’s no point in putting tariffs on bananas and coffee in the U.S. unless what you want is to basically put the equivalent of a “sin tax” on bananas and coffee because you’re weirdly morally opposed to people eating bananas and drinking coffee or something.
Fourth, tariffs don’t ever make domestic equivalents cheaper or more affordable for consumers relative to comparable foreign imports. They just drive the price of all available options up to or near the baseline cost of goods plus the tariff. In the absolute best case scenario where everything about tariffs works out as perfectly as possible, you’re just adding margin for producers.
Trying to be globally competitive economically by using tariffs makes no sense. Trying to improve domestic economic conditions by using tariffs makes no sense. It’s a ridiculously shallow, nonsensical approach to attempting to do either of those things even when they’re used carefully and responsibly, but they were never going to be used carefully and responsibly.
The point of them was always going to be to use them as a means of paying for indulgences and dispensations.
Though perhaps that’s a preferable policy than to re-shore sweatshops and child labor to the U.S. as you’re implicitly suggesting should be done?