From Unipolarity to Multipolarity: A Realist Explanation of 21st Century Great Power Rivalries

• SHANTA BARMAN

  Raiganj University

The post-Cold War liberal international order, premised on cooperative multilateralism, democratic convergence, and institutional rule-making, has increasingly been challenged by the resurgence of great-power rivalry and the diffusion of power across the international system. This article examines the transition from unipolarity toward multipolarity through a pluralist realist framework, integrating insights from classical, structural, and neoclassical realism. It focuses on the strategic competition among the United States, China, and Russia, with particular attention to Sino-American rivalry, Russia’s strategic posture in Europe, and the broader redistribution of global power. Employing a structured qualitative comparative case-study approach, the study examines military expenditure, technological capabilities, economic interdependence, and emerging instruments of power projection. It argues that international anarchy, state interests, and asymmetric distributions of power remain central determinants of great-power behaviour, while domestic political dynamics, strategic perceptions, and non-Western perspectives mediate their external strategies. The analysis further demonstrates that contemporary rivalry increasingly extends beyond conventional military competition to hybrid warfare, cyber deterrence, artificial intelligence, technological competition, economic coercion, and energy geopolitics, including emerging strategic competition in the Arctic. The article contends that Sino- American rivalry is becoming a defining axis of the twenty-first century geopolitics, while Russia’s assertive posture reflects, among other factors, its perceptions of NATO enlargement and post-Cold War strategic marginalisation. The emerging multipolar order, therefore, is characterised not simply by a redistribution of material capabilities but by increasingly complex and contested forms of power projection. By incorporating Global South perspectives into realist analysis, the article seeks to broaden the explanatory scope of realism and demonstrates its continuing relevance for understanding contemporary great-power competition and the evolving international order.

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