America’s first foray into rolling back prohibition 2.0 is barely underway, and already marijuana prices have dropped low enough to convince some cartel farmers in Mexico to abandon the crop. Mere months after two US states legalized marijuana sales, five Nobel Prize-winning economists released a UN report recommending that countries end their war on drugs. It would seem they were onto something. But in order to further decrease drug-trade violence in so-called producer states, the US first needs to legalize marijuana, but then also the US must stop using the UN to pressure producer countries into supply-based drug prohibition. Latin...