Under its covenant, the League of Nations was empowered to initiate sanctions against any nation resorting to war in violation of the covenant. Its declaration of an embargo against Paraguay (1934) derived from this power. Economic sanctions were applied against Italy during its invasion of Ethiopia (1935) in the League's most famous, and notably ineffective, use of its power.
The United Nations, under its charter, also has the power to impose sanctions against any nation declared a threat to the peace or an aggressor. Once sanctions are imposed they are binding upon all UN members. However, the requirement that over half of the total membership of the Security Council and all five permanent members agree on the decision to effect a sanction greatly limits the actual use of that power. UN military forces were sent to aid South Korea in 1950, and in the 60s economic sanctions were applied against South Africa and Rhodesia (now Zimbabwe). In the 1990s economic sanctions were imposed on Iraq after its invasion of Kuwait, and the Security Council approved the use of force to expel Iraqi forces from Kuwait. Sanctions were also imposed on the former Yugoslavia as a result of the Bosnian civil war and Kosovo crisis.
See R. Arens and H. Lasswell, In Defense of Public Order (1961); R. Segal, ed., Sanctions Against South Africa (1964); M. P. Doxey, Economic Sanctions and International Enforcement (1971) and International Sanctions in Contemporary Perspective (1987); D. Leyton-Brown, ed., The Utility of International Economic Sanctions (1987).