NATO's military intervention in Yugoslavia highlights the choices and problems confronting the alliance as it approaches the new century. An alliance created to keep Western Europe out of the Soviet orbit during the Cold War has sought to reinvent itself as a "crisis-management" organization to suppress conflicts on Europe's periphery - and perhaps beyond. Is NATO suited to playing such a role, or is the alliance a Cold War anachronism? How will Russia react to an enlarged NATO focused on out-of-area peacekeeping and conflict-prevention missions? Are there alternative security institutions that might better address Europe's security needs in the post-Cold War era?