Article 5 (NATO)

Article 5 of NATO’s founding treaty states that an attack on one member country is considered an attack on all member countries. This means that if any NATO member is attacked, the other members agree to respond collectively, including providing military support if necessary. It is a mutual defense commitment designed to ensure the security and stability of all members. However, the decision to take action is made collectively, and the article has been invoked only once, after the September 11, 2001 terrorist attacks in the United States.