American power and peril: The Trump doctrine and strategic fragmentation in the post-unipolar order

This article examines the Trump administration's departure from post-Cold War liberal internationalism and its consequences for the international order. Analyzing the "America First" doctrine through the lens of strategic fragmentation, it argues that Trump's unilateralism both reflected and accelerated structural transformations, including China's rise, Russian revisionism, and alliance erosion. Situating these developments within established theoretical frameworks-hegemonic stability theory, liberal order theory, and the sociology of norms-the analysis reveals how transactional diplomacy, systematic multilateral withdrawal, and explicitly conditional security guarantees simultaneously undermined institutional coherence and normative consensus. Biden-era continuities in China competition, technology restriction, and alliance management demonstrate that structural constraints-not merely leadership preferences-shape contemporary American foreign policy. The article concludes that the Trump administration represents an acceleration of long-term processes, not a temporary aberration that could be simply overcome. Strategic fragmentation differs from historic multipolarity, representing a deeper legitimacy crisis characterized by competing visions of international order that lack universal normative acceptance, with direct implications for defence planning in the Euro-Atlantic space.