General Discussion

Back in the day when they were used as a major source of revenue, industries were local. In short, we made stuff here out of resources we gathered here. They made stuff there out of resources they gathered there. There was no such thing as a just in time inventory system that sourced components from across the planet, no one could even do business remotely that way.

In that context, a tariff might protect a local industry cleanly by making competitive foriegn goods more expensive. Today, in that food, resources, and components are sourced globally, tariffs raise the prices for both domestic and foreign produced goods indiscriminately in varying amounts. in that parts and components might even cross a border more than once, there are potential compounding effects. Let's say the steel comes here and is tariffed at the border, it is then cut and stamped into parts here which are then shipped to Canada or Mexico for assembly being tariffed at the border, the assembled parts are then shipped back to be further assembled into a car here, tariffed again at the border....

These are simply an archaic idea that was never all that good in the first place