NATO Article 5 first invoked (2001)
After the September 11 attacks killed nearly 3,000 people in the United States, NATO invoked Article 5 for the first time in its 52-year history, declaring the attack an attack on all members. The alliance then joined operations in Afghanistan.
NATO began military operations in Afghanistan, its first combat deployment as an alliance.
Article 5 has been invoked only once; the Afghanistan campaign became NATO's longest war, lasting 20 years.
The Mecca pact mirrors NATO's Article 5 language. Its first activation will show whether a collective defense clause produces real deployments or stays symbolic.
