The way you improve the lot of foreign workers (a good idea) is by putting in place trade agreements that mandate worker protections. “You can only sell us cheap widgets if the working conditions are reasonable “. Two further points. 1 - with tariffs the worker exploitation continues, the goods just cost more (see example above) and 2 - look at the vibrant and dynamic US motorcycle industry for an example of the long term consequences of being insulated from competition.