It was Paul Krugman who said that productivity isn’t everything, but in the long run it’s pretty much everything. Yes, we all know, he’s a very irritating parti pris columnist at the New York Times. He’s also a Nobel Laureate economist whose expertise is trade. On this point he’s right.
Tariffs are a bad idea because they negate the very function of trade itself, protecting us from the competition that makes us richer.