This paper explores the evolving global landscape over the past two decades, emphasizing the imperative for alliances, particularly NATO, to earnestly reevaluate their objectives. The absence of a unified purpose is identified as a hindrance to alliances in delineating suitable policies, structures, and capabilities essential for goal attainment. The paper underscores the resilience of NATO as an alliance that remains pertinent amidst shifting security paradigms, acting as a deterrent to Russia and a values-centric framework for addressing challenges posed by China. Emphasizing the critical need for trust among alliance members, the paper explores potential risks, including eroding political will and accusations of transactionalism. Furthermore, it discusses NATO’s significance in preserving the security of Western democracies and highlights ongoing changes spurred by the conflict in Ukraine, leading to a renewed focus on alliance cohesion and expansion. The abstract concludes by noting the announcement of a forthcoming Strategic Concept to guide NATO’s activities in the next decade. Keywords: alliance, international system, security, cooperation.