The 1990s was a period of strategic innovation in US foreign policy. Operation Allied Force in particular represented an important step in the contorted evolution of America's attitude towards the use of force in the post-Cold War period. That operation demonstrated the growing influence of humanitarian concerns and the extent to which America was willing to reconsider Cold War criteria on the prudence and utility of force in support of its foreign policy. In its decision to intervene in Kosovo, the Clinton administration also divided opinion among the military. This, in effect, reduced the premium placed on the counsels of the armed forces and made it easier for the Bush administration subsequently to ignore their advice. Furthermore, having fought the war multilaterally through NATO, Operation Allied Force made America more wary of doing so again. In other words, the intervention set a number of precedents and left a significant legacy for the way in which US foreign policy was pursued in the decade that followed. This legacy is considered in two parts: the first analyses those issues associated with the use of force debate; the second considers how the Kosovo experience affected US attitudes to coalition warfare.