The development of a transatlantic security system after 1945 with NATO at its core gave security issues in the Western world a strongly interdependent character. This was paralleled by the institutionalized interdependence in the international monetary policies of roughly the same countries, which were all committed to a stable exchange-rate system and liberal trade policies. Both developments were closely connected, as this research has demonstrated, based on an analysis of the history of American and British troop maintenance in West Germany during the 1950s and 1960s. The Atlantic security system and the international monetary system were two sides of the same coin. Changes in one sphere invariably influenced the other. On the one hand, expansive American security policies after the war, whether they took the form of troop commitments abroad, foreign aid, or political pressure, played an essential part in bringing the dollar-gold system into existence. On the other hand, these policies were possible only in a system that protected the U.S. economy from the disruptive effects of its balance-of-payments deficits. The European side of the bargain was military protection and an international environment conducive to economic reconstruction and growth. Countries such as West Germany, which saw the provision of security by the United States as essential, adapted to the monetary system and actively supported it by extending credit to the United States. Britain, being less dependent, pursued an independent monetary policy at an increasingly high cost.