

Yes, as you said, they aren’t a new concept. We have plenty of evidence, of countries that tried that again and again. We know what he is doing is stupid.
Besides, your theory on tariffs won’t even get to be tested. Kidnapping people at random on the street and sending them to concentration camps has an overwhelmingly larger impact on the economy than the tariffs. People from outside of the US will only focus at this if you start to invade other countries, but at this point, nobody inside the US should be concerned with tariffs, at all.
No, they are too late for that.
They could if Trump picked another other to implement his policies.