Tariffs are a wonderful idea, aren’t they? A tariff – technically, a tax on an imported good, usually as a percentage of the good's value – sounds almost too good to be true. A tariff raises money on imports, but encourages Americans to stop importing, and to buy local goods instead of foreign; it serves a foreign policy purpose by punishing our enemies, and it helps pay for seaports and border protection. Quite a multifaceted, targeted tool. It’s like one of those magical diet pills that helps you get thinner in the waist, broader in the shoulders and chest, make...