... a tariff that is implemented to support an enviromental (or other social) objective must be shown to be the only way to conceivably pursue that objective.
You put the monkeys in charge of the banana plantation and this is the sort of nonsense that results.
You have specialists in international trade decide whether a specific policy is required to protect a certain endangered species, and they take the threat of trade restriction more seriously than the loss of a line of DNA that developed before we developed fire or language. I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
