The international order is often described today as returning to a world of spheres of influence. Yet that formulation is misleading. The current change is not a simple reversion to nineteenth-century geopolitics or great power concert, but rather the emergence of a far more unstable hybrid order, in which different organizing principles coexist and collide. Nowhere is that more evident than in the recent recalibration of U.S. grand strategy outlined by the Trump administration.

The 2025 National Security Strategy treats the Western Hemisphere as a sphere of influence, where the United States asserts its right to shape political and security outcomes. In contrast, the strategy defines the Indo-Pacific not as a U.S. sphere but a zone requiring strategic adjustment. In that zone, the United States seeks to deter China from becoming the dominant regional hegemon rather than to exercise direct regional primacy. This conflicting logic—recognizing a U.S. sphere in the Americas while not recognizing China’s potential sphere in the Indo-Pacific—already reveals a fundamental tension in U.S. grand strategy.

In classical international politics, stable spheres of influence could only exist when the strongest powers reached a form of great power concert—an implicit or explicit consensus among major states pertaining to the limits of their authority and restraint. A concert made spheres predictable and, in a limited sense, manageable. Today, however, such an understanding existing among the United States, China, and Russia is unlikely. Strategic distrust runs deep, ideological differences are vast, and technological rivalry has turned even economic interdependence into a security liability. Under those conditions, spheres of influence and their irrelevant applications are more likely to generate friction, miscalculation, and regional coercion.

The U.S. intervention in Venezuela highlights that dilemma. By asserting its hemispheric prerogatives through force, Washington undermines the principles it uses to oppose similar claims by powers elsewhere. In Asia, the danger is not simply China seeking a sphere of influence but also competing great powers normalizing incompatible regional orders with different rules, expectations, and hierarchies.

For South Korea and other Asian middle powers, that fragmentation of the global order poses a greater threat than any single sphere. Rather than adapting to rival zones of dominance, Korea’s long-term interest lies in reshaping the liberal, rules-based, and inclusive order that allows smaller states to have strategic autonomy, economic openness, and political choices. In a world drifting into regionalized power systems, South Korea should work with like-minded partners to prevent the Indo-Pacific from becoming a closed arena of great power entitlement—and to maintain an open space for cooperation, law, inclusiveness, and sovereign equality.

■ View Memo at CoC Website 

■ Chaesung CHUN_EAI President, Professor of International Relations at Seoul National University. 

■ Inhwan OH_EAI Senior Research Fellow, Lecturer at Seoul National University.

■ Edited by Sangjun LEE, EAI Research Associate
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