Introduction
The concept of security in the international system has undergone a profound transformation since the end of the Cold War. The collapse of the bipolar order not only altered the global balance of power but also reshaped the nature of threats, the functions of alliances, and the role of international institutions. Among the organizations most significantly affected by this transformation has been NATO. Founded in 1949 as a collective defense alliance against the Soviet Union, NATO served as the cornerstone of Western security throughout the Cold War. Following the collapse of the Soviet Union, however, the alliance’s strategic purpose, operational scope, and institutional relevance became subjects of sustained scholarly and policy debate.
In the post-Cold War period, NATO expanded beyond traditional territorial defense by engaging in crisis management, peace operations, counterterrorism, and regional stabilization. Operations in the Balkans, Afghanistan, and Libya have demonstrated the alliance’s ability to adapt to changing security environments, but they also exposed persistent disagreements regarding threat perception, burden-sharing, and the appropriate scope of collective action. These tensions have become increasingly visible as NATO members faced a more complex security environment shaped by the Russia-Ukraine war, China’s rise, Middle Eastern instability, and global energy uncertainty.
