The usual story, nicely summarized by the late Rüdiger Dornbusch and Sebastian Edwards, is that lax fiscal and monetary policies cause a flood of freshly printed currency to chase more dollars than the central bank can provide at the going exchange rate. Rather than let the currency depreciate, or tighten its policies, the government opts for foreign-exchange controls, limiting access to dollars to those who “really” need it and thus preventing “speculators” from hurting “the people.”