Power and Strategy in the 21st Century

Since the end of the Cold War, the United States has moved from unrivalled global dominance to a far more uncertain position in world politics. Power and Strategy in the 21st Century traces that trajectory, beginning with the optimism of the early 1990s and moving through the shocks of 9/11, the Global War on Terror, the 2008 financial crisis, and the rise of new challengers. It offers a clear, engaging account of how a period of unipolar confidence gave way to strategic overreach, growing constraints, and questions about America’s role in the international system.

Taking a regional approach, the book shows how U.S. influence has shifted in Europe, East Asia, the Middle East, South and Central Asia, the Western Hemisphere, and Africa, since 9/11. Each chapter examines how American policies (ranging from diplomacy and military interventions to economic statecraft) have shaped local dynamics and contributed to broader patterns of imperial overstretch and decline. This structure enables grounded understanding of how global power is exercised differently across regions and why outcomes vary so widely.

Designed for courses in U.S. foreign policy and international relations, Power and Strategy in the 21st Century provides a concise, accessible framework for understanding American power today. It equips readers to assess competing explanations for U.S. decline and to think critically about where the international order may be heading next.

Armin Krishnan is an Associate Professor of Security Studies at East Carolina University, where he teaches courses on international security, American foreign policy, and intelligence studies. His most recent publications are Havana Syndrome: The Threat to National Security (Bloomsbury 2025) and Fifth Generation Warfare: Dominating the Human Domain (Routledge 2024). His previous research included books on military contracting, autonomous weapons, and military neuroscience. He has published in the Brown Journal of World Affairs, Intelligence and National Security, Contemporary Security Policy, and the Journal of Strategic Security.

Hanna Samir Kassab is an Associate Professor of Political Science and Security Studies at East Carolina University. He teaches courses in national security, foreign policy, and global politics. His most recent books Multipolar Revisionism and Cutting the Cost of American Hegemony: The Long-Run is Here (2026) and Post-Colonial Realism: Cultural Conflicts, Cuisine, and the Changing International System (2025) are published by Routledge. His journal articles include “Mackinder’s Heartland Thesis and the Belt and Road Initiative: Russia’s Growing Dependence on China in the Aftermath of the Ukraine War” in Brazilian Journal of Strategy & International Relations and “Prestige, Humiliation and Saving Face: National Identity and Great Power Politics” in Contemporary Military Challenges.