Article 51 of the United Nations Charter states that:
Nothing in the present Charter shall impair the inherent right of individual or collective self-defense if an armed attack occurs against a member of the United Nations, until the Security Council has taken the measures necessary to maintain international peace and security. Measures taken by Members in the exercise of this right of selfdefense shall be immediately reported to the Security Council and shall not in any way affect the authority and responsibility of the Security Council under the present Charter to take at any time such action as it deems necessary in order to maintain or restore international peace and security.
International lawyers are still arguing about the scope of the right of self-defence in Article 51 of the U.N. Charter. Most of the arguments focus on the semantics of Article 51. Those who argue for a “restrictive view” of the provision emphasise the qualifying phrase “if an armed attack occurs”.