Of all the threats to global security in the modern era, none is more catastrophic in its effects than the failure of states and international organizations to act when large scale human rights atrocities (meaning genocide or ethnic cleansing) occur. The international community promised that the genocide of World War II would never repeat itself at the Convention on the Prevention and Punishment of the Crime of Genocide in 1948. Unfortunately, the 20th century's final decade ended in a bloody fashion as acts of genocide and ethnic cleansing occurred in Iraq, Somalia, Rwanda and Bosnia. In each of these cases, the international community either failed to act or intervened only after the carnage and suffering was too monumental to ignore. The only time the international community acted to prevent a potential genocide during this period was in Kosovo in the spring of 1999. The escalating Serbian violence and aggression against the Albanian Muslim population of Kosovo prompted the North Atlantic Treaty Organization (NATO) to launch an air campaign against Serbia to stop the atrocities. The purpose of this paper is to examine the intervention in Kosovo as it provides an excellent foundation for the development of a credible humanitarian intervention policy.