The case against protectionism is based on the theory of comparative advantage.
Mathematically, that theory is hard to refute, unless there is something wrong with the assumptions, to wit:
- Free mobility of labor
- Costless and easy retrainability
I don’t think either of those things are always true. If you’ve been trained to do a job for 25 years, settled in an area and have a family, it isn’t going to be easy for you to relocate, and it may not be cheap or quick to retrain you to a new skill. Further, that new skill—which will be in the areas which would have comparative advantage going forward—may not be immediately evident.
If the users of the theory incorporated some of these issues—which show up as socialized costs—into the cost of the items being made, I think that sometimes protectionist policies, or at least a multi-year taper into the new production regime, would be cheaper. The displacement costs are never considered, it seems to me.
And the ones prevented from opening for similar reasons ?
Does Trump really want tariffs, or is he using the the threat of imposing tariffs to get the best possible deal?
Your starred assumptions may be better described as:
- The fungibility of mundane labor.
To wit: work that pretty much anyone can do with minimal training can be done anywhere by anyone. The “mobility” you note isn’t that workers can move, it’s that the work can - to wherever cheaper labor can be found.
Those same effects arise from competition within the country as well from abroad. But, in both cases, the competitors would not be successful unless they were providing value.
Overall wealth increases, but there are losers as well as winners. E.g., a million people get cheaper cars, but a thousand need to get new jobs.