The Impossible Trinity (or Trilemma) in international economics states that a country cannot simultaneously achieve all three of the following goals: a fixed exchange rate, independent monetary policy, and free capital movement (capital account openness). A country must choose to forgo one of these goals. For example, a country can have a fixed exchange rate and free capital movement, but it will lose the ability to conduct an independent monetary policy (as monetary policy must be used to maintain the exchange rate).