ASIL Insights

On August 20, American cruise missiles struck targets in Afghanistan and Sudan. The target in Afghanistan was identified as an extensive terrorism training complex. U.S. officials said that the United States had convincing evidence that the organization of Osama Bin Laden was responsible for the bombings of U.S. embassies in Kenya and Tanzania on August 7, and that a meeting of members of an international terrorist network he supported was imminent at the Afghan site when the missile attack occurred.

The target in Sudan was a factory that American officials said made a precursor element used in the production of a potent nerve gas. Sudanese officials said that it was a pharmaceutical plant.

Bill Richardson, U.S. Ambassador to the United Nations, said that the attacks were carried out only after repeated efforts had been made to convince the Sudanese government and the Taliban regime of Afghanistan to cease their cooperation with the Bin Laden organization. President Clinton described the missile strikes as acts of self-defense and of retribution for the bombings of the embassies in Kenya and Tanzania.

Article 51 of the United Nations Charter recognizes the inherent right of self-defense if an armed attack occurs against a UN member, until the Security Council has taken measures necessary to maintain international peace and security. The inherent right of self-defense antedates the Charter. It is subject to two conditions: the necessity of the use of force for defensive purposes, and the proportionality of the force actually used to the force defended against.

A widely accepted test of necessity dates back to 1842 when U.S. Secretary of State Daniel Webster rejected a British claim of self-defense arising out of a raid on a small steamship that was being used in support of a Canadian insurrection against Great Britain. A British raiding party boarded the ship while it was moored on the New York side of the Niagara River, attacked those on board and set it afloat over Niagara Falls. Webster said that although a right of self-defense existed, it should be confined to cases in which the "necessity of that self-defence is instant, overwhelming, and leaving no choice of means and no moment for deliberation." The British government acquiesced in that test, and it was adopted by the International Military Tribunal at Nuremberg after World War II. It has sometimes been questioned since the Nuremberg trials, primarily in the context of defense against a threatened nuclear attack.

The proportionality aspect of self-defense comes into play if the necessity test has been met. It has been formulated in either of two ways. It could mean that the intensity of defensive force must be approximately the same as that defended against, or it could mean that the defensive force-even if more intensive-is permissible so long as it is not designed to do anything more than defend against the reasonably perceived threat. There is no authoritative international decision favoring one of these formulations over the other.

International law recognizes a limited right of reprisal (retaliation) in addition to the right of self-defense. It is a form of self-help legitimizing certain action that would otherwise be unlawful, in response to an illegal act by or under the aegis of another state. It, too, is subject to the general requirements of necessity and proportionality, though they are not in all respects defined or applied in the same manner as in connection with the right of self-defense. In particular, the right of reprisal includes a requirement that non-coercive means of settling the matter be attempted before a reprisal is carried out. There is a substantial body of legal opinion that the UN Charter further limits permissible reprisals to measures other than armed force, since Article 2(4) prohibits any "threat or uses of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations." This would still permit the use of armed force if it meets the requirements of self-defense.

About the author:
Frederic L. Kirgis is Law School Association Alumni Professor at Washington and Lee University School of Law. He has written a book and several articles on United Nations law, and is a member of the Board of Editors of the American Journal of International Law.