Many economists expect catastrophic consequences if any country exits the euro. However, during the past century sixty-nine countries have exited currency areas with little downward economic volatility. The mechanics of currency breakups are complicated but feasible, and historical examples provide a road map for exit.

The real problem in Europe is that EU peripheral countries face severe, unsustainable imbalances in real effective exchange rates and external debt levels that are higher than most previous emerging market crises. Orderly defaults and debt rescheduling coupled with devaluations are inevitable and even desirable. Exiting from the euro and devaluation would …