We are discussing Article 5 of the North Atlantic Treaty Organisation. And not only

The Parties agree that an armed assault on 1 or more of them in Europe or North America will be deemed to constitute an assault against all of them, and so agree that if specified armed assault occurs, each of them, in the exercise of the right to individual or collective self-defense recognised under Article 51 of the Charter of the United Nations, will assist the organization or Parties assaulted by taking, without delay, as well as in consultation with the another Parties, the action he considers necessary, including the usage of armed forces to reconstruct and keep the safety of the North Atlantic area. Any specified armed assault and any measures resulting from it shall be notified without hold to the safety Council. specified measures shall be abandoned as shortly as the safety Council takes the essential measures to reconstruct and keep global peace and security.