you're talking about comparitive advantage, but you fail to realize two things. 1. in economics, everything is a series of tradeoffs. science can tell you how to design a car which drives very fast in a straight line, but that car would be shit for driving day to day. you want to be able to steer it, you want it to be fuel efficient, etc. comparitive advantage brings efficiency at the loss of stability. when your country's medical equipment is all produced in another country which gets locked down due to a pandemic, this becomes obvious. 2. this isn't only an economic issue, but a negotiation issue. he is trying to get a better deal with other countries by threatening to do something which would be very bad for their economies (since they depend on the american market). read what he has actually said one more time. he specifically points out the behavior of certain other countries, indicating it will not be all countries across the board, and it will be targeted based on behavior. if you knew shit about negotiation or had any pattern recognition, you would see he uses this same tactic all the time to great effect. anyway, going to bed now.
United States