Since the days of Giulio Douhet, airpower theorists and practitioners have hotly debated the best use of airpower for achieving political objectives. Academics and airmen have written and tested several theories on the use of coercive air power. Currently, three main theories of coercive airpower are in vogue within academic and airpower circles--denial, punishment, and balance of interest. This study examines NATO's Operation ALLIED FORCE within the construct of these three theories. The first section summarizes the conflict from both a military and diplomatic perspective. It splits the 78-day conflict into four phases and uses foreign and domestic press reports, NATO-member after action reports, and US Air Force data to determine NATO and Belgrade's objectives, strategy, and actions between March and June of 1999. It then uses the historical record to ascertain the fit between the facts of the conflict and the three theories of coercion. Using the denial theory of Robert Pape, the punishment theory of Thomas Schelling, and the balance of interest theory of Alexander George and William Simons, section two of this study determines which theory best explains the outcome of NATO's air war over Serbia. Finally, the third section of this study reveals that two of the three theories are consistent with the historical record. Thomas Schelling's punishment theory fits the operational-level history of the conflict and seems to explain why Belgrade capitulated. George and Simons' balance of interest theory is also congruent with the facts, but it fits the geo-political history of the conflict and seems to explain the timing of Belgrade's decision to accept NATO's terms. This unexpected finding that two schools of coercion are supported by the same case study leads to the implication that different theories of coercion are not necessarily mutually exclusive, but are instead potentially complementary.