restoring equilibrium

When a country chronically runs a balance-of-payments,we say it has pegged its exchange rate at too high a level.Its costs are not competitive.it is said to have an overvalued currency. Consider the country it is trading with.That country must be running a chronic surplus.Its currency is said to be undervalued. How to cure the disequilibrium?Economists say;"Depreciate the overvalued currency.What is exactly the same thing-repeat,exactly-appreciate the undervalued currency.That should tend to help restore balance-of-payments equilibrium. Politically,it seems always harder to get a country to appreciate than to depreciate.Thus,in Germany,which was the nation with the most stubborn international surplus in the last dozen years,vested interests grew up in their swollen export industries.They hated to see the surplus go.