When diplomacy failed, war used to be inevitable, the continuation of politics by other means. Today, when persuasion doesn’t work, big powers turn to economic combat as their first resort. Sanctions occupy a messy zone between condemnations and air strikes. Hard to organize and uncertain in impact, they can hurt innocent citizens and legitimate businesses. Russia’s seizure of Crimea and support for separatists in eastern Ukraine are putting the effectiveness of sanctions to their latest test.