A Clear Victory for Air Power: NATO's Empty Threat to Invade Kosovo

Why did Yugoslav President Slobodan Milosevic surrender control of Kosovo to NATO on June 9, 1999? Two reasons are most commonly cited: (1) the likelihood of continued and intensified NATO air strikes, and (2) the alliance's threat to launch a ground war. The distinction between the two is an important one. If NATO's ground threat did not play a role in Milosevic's decision to surrender, then Operation Allied Force, launched on March 24, 1999, demonstrates the ability of coercive air power—and air power alone—to achieve a major political goal. If, however, the ground threat factored into Milosevic's decisionmaking, then the Kosovo conflict serves as an example of the inherent difficulty of relying on air power alone to achieve political goals, even under favorable conditions.

The conventional view of the war in Kosovo holds that the threat of ground invasion was an essential element of NATO's success. According to Daniel Byman and Matthew Waxman, this threat "probably played the largest role in motivating Milosevic's concessions." ¹ Ivo Daalder and Michael O'Hanlon argue that the turning point occurred when U.S. officials began to threaten a decisive invasion. ² Benjamin Lambeth contends that "there [was] no question that by the end of May, NATO had yielded to the inevitable and embraced in principle the need for a ground invasion....There is also every reason to believe that awareness of that change in NATO's position...figured importantly in [Milosevic's] decision to capitulate." ³ In his memoirs, NATO's former Supreme Allied Commander in Europe (SACEUR), Gen. Wesley Clark, concurs with this assessment. ⁴

This article argues that the conventional wisdom about the role of the ground threat in ending the war in Kosovo is mistaken, and it offers new evidence to support this claim. The signals sent by both President Bill Clinton's administration and NATO that they were preparing to shift to a ground operation were weak and appear credible only in hindsight. Both politically and militarily, NATO sent strong signals to Milosevic that it was highly averse to casualties and risk taking, signals that were still being sent even toward the end of the conflict. Serious obstacles to a ground operation (e.g., the lack of consensus among NATO's members in support of an invasion), though broadly discussed by U.S. officials and the media, were never confronted. Moreover, even if NATO's members had agreed on the need for a ground operation, Milosevic could have been assured that military preparations for such an offensive would have required a lengthy deployment period, a period that would have promised him numerous opportunities to find a negotiated solution to the conflict. The possibility of a U.S. or NATO invasion of Kosovo appears to have played no more than a minor role in the final round of negotiations with Milosevic, and the recollections of key participants usually omit it entirely. I argue that Milosevic did not change his mind about NATO's strategy because (1) there are no strong indications that he did, (2) there are many reasons and some evidence that suggest that he did not, and (3) NATO's ground threat remained weak. Thus, the threat of continued and intensified aerial bombardment was the only necessary military condition for Milosevic's decision to accept NATO's terms. As a result, the conflict offers an example of the successful use of coercive air power. ⁵

The Kosovo case is important for scholars and practitioners alike. Much of the recent scholarship on the use of coercive air power casts doubt on its ability to independently obtain major political and strategic goals. The most prominent work in this regard is Robert Pape's Bombing to Win. ⁶ Pape's theory argues that coercive air campaigns are likely to meet with success only when the coercer can credibly demonstrate that...