In April 1999, the North Atlantic Treaty Organization (NATO) will turn fifty. Back in 1949, few political observers would have guessed that the twelve-member alliance would survive for half a century and take in Greece and Turkey on 18 February 1952, West Germany on 6 May 1955, and Spain on 30 May 1982. Even fewer would have predicted that the Czech Republic, Hungary, and Poland – three ex-Warsaw Pact allies – would be scheduled to join on NATO's fiftieth anniversary. NATO played a crucial role in stopping Soviet aggression during the alliance's first few decades. Without question, NATO helped to win the Cold War by outlasting the former Soviet Union and Warsaw Pact in a war of attrition that diverted scarce resources to the defense sector. To keep up with the technically superior Western defense industries, the former Soviet Union had to allocate so many resources into its defense sector that tremendous strains were placed on its economy, which are still being felt today. Economic inefficiencies in the Soviet Union also played a significant role in its Cold War defeat. Of course, the NATO allies also paid for their own diversion of resources in terms of growth and prosperity.

NATO has been a resilient institution that has withstood France's and Spain's exit from the integrated military structure, significant alterations in its military doctrine, hostilities between Greece and Turkey, leadership crises within its allies, policy differences among its members, and major changes in weapon capabilities.