What are the obligations of NATO members toward one another?
NATO is based on the principle of “collective defense,” which means that an attack on one member is considered an attack on all members. Article 5 of the NATO Treaty states that, if one of the members is attacked, each member will take “such action as it deems necessary, including the use of armed force” to restore security. Has NATO ever acted to defend the United States? On September 12, 2001, NATO took the historic action of invoking for the first time Article 5 of the NATO Treaty. This Article embodies the principle of collective defense that an attack on one member is an attack on all. The Alliance backed up this action by sending five AWACs [Airborne Warning And Control] aircraft and a detachment of 200 personnel to the United States in October 2001. These aircraft logged 3,000 hours patrolling American skies and protecting North American airspace. In addition, NATO ships patrolled the Eastern Mediterranean to keep terrorists from infiltrating into Europe, and all NATO allies hav
