Do middle powers matter geopolitically to great powers when confronting the unconventional, twenty-first-century threats from nation-states or nonstate actors? By studying certain middle power politics in the heart of early, anarchical, and volatile post-Cold War Europe, we can better grasp the impact such middle powers have in the aftermath of September 11, 2001. Bridging the European Divide explores how key regional middle powers perceived and advocated their political power options, and tells the largely untold story behind the motives of significant middle power decisions and repercussions. Such regional alignment decisions stemmed from the ideas, opportunities, and realities necessary to transform nation-states amid acute regional uncertainty, global upheaval, and international systemic change. In order to achieve a better understanding of how to bridge the post-9/11 gap between changes in material incentives and the role of ideas, Spero smartly connects two different types of power politics-ways of assessing security dilemmas and foreign policy decisions, and reasons why middle powers and their geopolitical roles matter to great powers.