Self-Defense

Humanity has always recognized that individuals should have the right to defend themselves from violence. In international law this basic normative intuition is codified for states in the Charter of the United Nations, Article 51 (see Randelzhofer 2002, cited under Conditions in Article 51). Article 51 is an exception to the Charter’s general prohibition on the use of force found in Article 2(4). The prohibition on the use of force is at the heart of the Charter, given that the most fundamental aim of the Charter and the UN organization created by the Charter is to “save succeeding generations from the scourge of war” (Preamble). It stands to reason that any right to use force as an exception to the general prohibition on resort to force would be narrow. Article 51 permits a state to act in unilateral or collective self-defense only “if an armed attack occurs.” This article concerns the international law exception to the prohibition on force for self-defense. The commentary on Article 51 is extensive and generally falls into one of two categories: first, scholarship, judicial decisions, and government policies that support Article 51’s plain terms; second, scholarship and government policies that advocate expanding the right to use force beyond Article 51’s provisions. The writers in these two categories have various labels but are most commonly referred to as the “strict” interpreters versus the “broad” interpreters. One author refers to the groups as the “restrictivists” versus the “antirestrictivists.” The divergence of views can be explained to some extent by the differing assessments writers make about the utility of resort to military force. The UN Charter was drafted at the end of World War II, when confidence in military force was certainly low and commitment to ending the use of force was high. Fifty years later, perhaps frustrated by the lack of success with other means, writers (especially in a few militarily powerful states) urged relaxing the rules against force to respond to terrorism, weapons programs, and computer network attacks. Some try to justify force under the principles of necessity and proportionality, rules beyond the UN Charter but equally important in the long history of normative thinking on killing in self-defense.