Actions under Article 5 following the 9/11 attacks
On 11 September 2001, the United States was struck by brutal terrorist attacks that killed and injured thousands of people. The Alliance’s response to 9/11 saw NATO engage actively in the fight against terrorism, launch its first operations outside the Euro-Atlantic area and begin a far-reaching transformation of its capabilities. Moreover, it led NATO to take action under Article 5 of the North Atlantic Treaty for the first and (so far) only time in its history.
Showing solidarity
On 11 September 2001, the North Atlantic Council issued a statement condemning the attacks and expressing solidarity with the United States. On the evening of 12 September 2001, less than 24 hours after the attacks, Allies met in the North Atlantic Council. The Council agreed “that if it is determined that this attack was directed from abroad against the United States, it shall be regarded as an action covered by Article 5 of the Washington Treaty”. NATO Secretary General Lord Robertson subsequently informed the Secretary-General of the United Nations of the Alliance’s decision.
On 2 October 2001, once the Council had been briefed on the results of investigations into the 9/11 attacks, it determined that they were effectively regarded as an action covered by Article 5.
Taking action
In the following weeks, consultations among the Allies were held and collective action was decided by the Council. This was without prejudice to the United States’ right to carry out independent actions, consistent with the United Nations Charter.
On 4 October 2001, NATO agreed on a package of eight measures to support the United States:
- to enhance intelligence-sharing and cooperation, both bilaterally and in appropriate NATO bodies, relating to the threats posed by terrorism and the actions to be taken against it;
- to provide, individually or collectively, as appropriate and according to their capabilities, assistance to Allies and other countries which are or may be subject to increased terrorist threats as a result of their support for the campaign against terrorism;
- to take necessary measures to provide increased security for facilities of the United States and other Allies on their territory;
- to backfill selected Allied assets in NATO’s area of responsibility that are required to directly support operations against terrorism;
- to provide blanket overflight clearances for the United States and other Allies’ aircraft, in accordance with the necessary air traffic arrangements and national procedures, for military flights related to operations against terrorism;
- to provide access for the United States and other Allies to ports and airfields on the territory of NATO member countries for operations against terrorism, including for refuelling, in accordance with national procedures;
- that the Alliance is ready to deploy elements of its Standing Naval Forces to the Eastern Mediterranean in order to provide a NATO presence and demonstrate resolve;
- that the Alliance is similarly ready to deploy elements of its NATO Airborne Early Warning Force to support operations against terrorism.
On the request of the United States, the Alliance launched its first-ever anti-terror operation – Operation Eagle Assist – from 9 October 2001 to mid-May 2002. This operation consisted of seven NATO AWACS radar aircraft that helped patrol the skies over the United States; in total, 830 crew members from 13 NATO countries flew over 360 sorties. This was the first time that NATO military assets were deployed in support of an Article 5 operation.
On 26 October 2001, the Alliance launched its second counter-terrorism operation in response to the attacks on the United States, Operation Active Endeavour, which involved elements of NATO’s Standing Naval Forces patrolling the Mediterranean Sea to detect and deter terrorist activity, including illegal trafficking. Initially an Article 5 operation, Active Endeavour benefitted from support from non-NATO countries from 2004 onwards. The operation ended in 2016.