The North Atlantic Council of NATO authorized Activation Orders for air strikes against Yugoslavia on October 13, 1998, tying its directive to UN Security Council Resolution 1199. In that resolution, the Security Council expressed deep concern about the excessive force being used by Serbian security forces, declared the situation a ŗthreat to the peace and security in the region,˛ and resolved to consider further action to maintain peace. 
The roots of the conflict, however, went back much further. Kosovo, a province of Yugoslavia 90% ethnically Albanian, was stripped of its semi-autonomous status in 1989. A violent form of Kosovo nationalism arose in the mid-1990s as a reaction to the Serbsš push for Greater Serbiaš throughout the region (exemplified in the 1991-1995 slaughter of Muslims in Bosnia-Herzegovina). Serbians had deep attachment to Kosovo because of its historical and religious importance to the Serbian Orthodox Church, and the 1389 Battle of Kosovo resulted in 500 years of subjugation of Serbians by the Ottoman Turks. The deep historical significance of the region, combined with severe ethnic nationalisms, lead to a ruthless conflict against the ethnic Albanians already living within the region.
By the time of Resolution 1199, the humanitarian situation in Kosovo had become ghastly. Serbian forces had killed 2,000 people and displaced 450,000 from their homes before NATOšs intervention even began. The ethnic cleansing directed against Kosovars resulted in 226,000 refugees in Albania, 125,000 in the former Yugoslav Republic of Macedonia, and 33,000 in Montenegro, all before NATOšs Activation Orders. By the time NATO began its air campaign, an estimated 1.5 million people (90% population of Kosovo) had been expelled from their homes, 5,000 Kosovars had been executed, and some 225,000 Kosovar men were missing.
Worse still, the UN had proven itself unable to act. Initially, Resolution 1160 enacted an arms embargo under Chapter VII power, but it never identified the specific threat to international peace. Even while recognizing the full fury of Serbian human rights atrocities, Resolution 1199 resolved only to ŗfurther consider˛ action. The October NATO Activation Order forced the Yugoslav government to accept an air verification regime and an OSCE Kosovo Verification Mission (KVM), and the Security Council finally endorsed the NATO agreement in Resolution 1203 (with a mild remonstrance that it still had primary authority for international peace).
After continued Yugoslav aggression, NATO threats lead both sides to negotiations in Rambouillet, France, in February 1999. The Serbs soon left the talks and immediately intensified operations against the Albanian Kosovars, breaching compliance with the October 1998 agreement. After further spurned negotiation attempts by NATO, the Alliance began air strikes against Yugoslavia on March 23, 1999. The bombing campaign was halted on June 10, with the withdrawal of Serbian forces from Kosovo, and the signing of the Military-Technical Agreement on June 9, 1999. NATO then notified the UN Secretary General Kofi Annan of the agreement, who encouraged both sides to comply with the agreement. The Security Council passed Resolution 1244 (14-0, China abstained), accepting the end of hostilities under the agreement.
Was the NATO intervention in Kosovo legal under international law? As a regional organization performing an enforcement action against a sovereign state without Security Council authorization, the principles of international law should resoundingly answer ŗno.˛ But international law is a product of its political system- a construct of the norms, standards, principles and institutions of that society. Thus, it is the application of the norms of the international community to the principles of international law, and not the principles themselves, which matter under international law. And from this perspective, NATOšs action was most definitely legal. When NATO began its action against Yugoslavia, it gave no official legal justification for its action. The NATO Secretary General gave ŗlegitimate grounds,˛ for action, but formulated no real legal support. Similarly, the US articulated no legal theory, other than justifications such as Serb violations of international law, violation of OSCE, NATO, and UN Security Council agreements, and violation of Yugoslav War Crimes Tribunal agreements. Similarly, the May 10-11 arguments by individual NATO nations before the International Court of Justice revealed inconsistencies and incompleteness in NATOšs legal justification.
Legal scholar Sean Murphy reviewed six arguments potentially justifying NATOšs action, and found none convincing:
1) Expansive reading of Article 2(4), allowing coercion not directed at the sovereignty of a state, (being inconsistent with the Charter principles, and finding no humanitarian intervention intent to the Charter creation);
2) Security Council authorization of force through Resolutions 1199 and 1203 (stating Russia and China directly opposed force and would have vetoed any such resolution);
3) Article 51 defense, (finding little threat and no armed attack against NATO);
4) Chapter VIII protection of international peace by regional organizations, (noting Article 53 requires UN authorization for all enforcement action);
5) international community involvement since 1991, such as previous Security Council resolutions in Balkans, (stating would incredulously authorize force in any case where Security Council passed a resolution for a particular crisis); and
6) pure humanitarian intervention doctrine under contemporary international law, (finding no real support for this doctrine in the UN Charter).
The real justification, states Murphy, comes from the international communityšs reaction to NATOšs intervention. All nineteen NATO members, and many non-NATO members, supported the intervention. A March 26, 1999, Security Council resolution to condemn the intervention failed 12-3; states supporting NATOšs intervention included non-members such as Argentina, Bahrain, Brazil, Gabon, Gambia, Malaysia, and Slovenia. Additionally, the General Assembly never condemned the action, as it did during the US intervention of Grenada in 1983 and Panama in 1989. Most telling, the Security Council blessed the cease-fire fruits of the intervention under Resolution 1244. In the end, the global communityšs reaction clearly sanctioned NATOšs intervention.
Thus, Murphy sees the NATO intervention as a law-shaping event, where international law now lies somewhere between two extremes. At its broadest interpretation, Kosovo stands for the rule that a coalition of states may intervene in any other state where it anticipates widespread deprivations of human rights. At its narrowest interpretation, Kosovo stands for the rule that intervention may proceed when a) the Security Council has expressly identified threats to international peace or humanitarian catastrophe; b) the government refuses Security Council demands and its own previous agreements; c) a state coalition intervenes to prevent humanitarian crisis; d) those states use necessary and proportional force; and e) the Security Council does not condemn the intervention.
No matter where the final principle will be determined in international law, the fact is the international community has sanctioned a law-shaping event in the NATO humanitarian intervention in Kosovo. This principle will undoubtedly continue to be elaborated and refined as future international crises require, as was nearly demonstrated in the chaos that erupted in East Timor not four months after the bombs stopped in Kosovo