How international trade restriction crippled world trade?

Answer 1

You have tariffs that raise prices. You have inspections,say for meat and vegtables, that raise costs. You have bans like: you can't import cocaine into the US. But you also can't import genetically engineered livestock or beef or crops into some countries. There might even be bans on import of pork products into certain countries, for instance, that would limit the free flow of goods. Oh, and Western countries prohibit the export of defends products to certain countries. And we refuse ANY trade with Cuba, so we don't get their cigars, at least not directly and more cheaply, and so they costs more than ordinary. Same with Cuban sugar and, I guess rum or other sugar products.