The North Atlantic Treaty Organization (NATO) initiated Operation Deny Flight at the request of the United Nations (UN) Security Council in April 1993, in response to the ongoing war in Bosnia-Herzegovina. Two and one-half years later, in December 1995, Deny Flight officially ended after an almost continuous 970-day aerial presence constituting over 100,000 aircraft sorties. In that time, NATO aircraft dropped more than 3,000 bombs while participating in combat operations for the first time in alliance history. Deny Flight's initial mission was to enforce a UN Security Council mandated no-fly zone over Bosnia. This mission expanded in the ensuing months to include close air support when requested for UN protection forces (UNPROFOR) on the ground and to deter Serb aggression against six UN-designated safe areas. By August 1995, warring Croats, Muslims, and Serbs had consistently violated the no-fly zone. The UN had documented over 5,000 airspace violations, primarily by helicopters. Serbs, Croats, and Muslims had killed or wounded over 100 UNPROFOR soldiers and aid workers, and the Serbs had overrun three of the six designated safe areas. Serbs had also used UNPROFOR soldiers as human shields to guard against NATO air strikes. NATO took a more forcible stance with Operation Deliberate Force which was designed to break the so-called siege of Sarajevo and get peace negotiations back on track. Whereas Deny Flight was generally ineffective in its mission, Deliberate Force was, in the word's of US Secretary of Defense William Perry, "the absolutely crucial step in bringing the warring parties to the negotiating table at Dayton, leading to the peace agreement." To understand the role Deny Flight and Deliberate Force played in getting a peace agreement signed, one must understand the political and historical context of the war in Bosnia-Herzegovina. Ethnic animosities, severe economic hardships, and opportunistic leadership, combined with an uncertain post-cold-war landscape, merged to create a confusing and dangerous situation in Bosnia. By the late summer of 1995, the Bosnian Serbs, who early on controlled 70 percent of Bosnia, were in retreat. Serbia cut off its economic and political support of the Bosnian Serbs and a Bosnian/Croat Confederation Army had been gaining ground against the beleaguered Serbs throughout the spring and summer. Facing defeat and domination, the Bosnian Serb Army was a ripe target for a coercive bombing operation. Deliberate Force proved to be the coercive catalyst that led to the Dayton peace agreement and the current cessation of hostilities.