In This Article Expand or collapse the "in this article" section Alliance Commitments in the Twenty-First Century

  • Introduction
  • Hub and Spokes: United States and Bilateral Alliances in Asia
  • Retrenchment and “Rebalancing”
  • China and Its Security Cooperation

International Relations Alliance Commitments in the Twenty-First Century
Paul van Hooft
  • LAST REVIEWED: 24 May 2018
  • LAST MODIFIED: 24 May 2018
  • DOI: 10.1093/obo/9780199743292-0233


The predominant focus of the scholarship on alliances and security commitments in the 21st century is on how the range of multilateral and bilateral relationships are adapting to the rapidly changing international environment. Most of the existing relationship, with few later additions, date back to the Cold War. However, the existing frameworks are being put under pressure internationally and domestically, from the growing economic and military power of China in Asia, Russian attempts to regain their sphere of influence and push back against the expansion of NATO and the European Union, and increasing anti-internationalist sentiments within the United States as well as in Europe and Asia. The United States has acted—or according to some critics, purported to act—as the key security provider and pacifier of intra-regional conflicts in Europe and Asia. Those security arrangements have been organized multilaterally through NATO in Europe, and through a “hub-and-spokes” model in Asia. Enduring themes within the scholarship on alliances have again been brought to the fore: the risks of abandonment and entanglement (or entrapment); the specific risks that guarantees of extended nuclear deterrence bring; debates over equitable burdensharing between allies; and whether allies are hedging against the power of the United States, or at least against a possible American withdrawal. i As in the Cold War, a great amount of attention is being paid to the credibility of the United States, when it comes to deterring adversaries and reassuring allies of its commitments in their respective regions. The debate of alliances and security commitments, therefore, has implications for larger discussions, whether on the future of American grand strategy, or on how China will engage with the existing global order, or on the likelihood of international conflict.

The United States and Its Alliances

The United States is the key actor of most existing alliances and security arrangements in the 21st century. The United States has been the unipolar power after the Cold War: Walt 2009 gives an overview of the theoretical implications thereof. It has continued to remain engaged globally, after the end of the Cold War, and maintained the obligation to defend a collection of over sixty states that span five continents and account for three-quarters of global economic output. Proponents of the American presence, such as Art 2003 and Brooks and Wohlforth 2016, argue that the United States still has an important role to play as a regional security provider and intra-regional pacifier in Europe, Asia, and the Middle East. In contrast, Posen 2014 and Layne 1997 argue that the United States has overcommitted and should withdraw itself from dangerous and free-riding alliances. Why the United States has done so, despite the costs and risks of burdensharing and entanglement, has been explained in Dueck 2008 and Layne 2006. Both scholars argue that the willingness to derive from deeply engrained liberal beliefs among American policymakers that equate American security and prosperity with maintaining a liberal democratic order. Alliances have benefits for the United States beyond adding capabilities: Kreps 2011 argues that the United States has often intervened multilaterally to increase legitimacy. In short, its alliances are a fundamental part of US grand strategy with spillover effects on the other parts of its strategy, and which consequently serve a variety of national interests.

  • Art, Robert J. A Grand Strategy for America. Ithaca, NY: Cornell University Press, 2003.

    In this comprehensive book, Art argues that a post–Cold War US grand strategy of selective engagement should continue to be internationalist and based on forward defense. Art builds on his earlier writing on the fungibility of force, of how force has spillover effects in other domains. Though it is ambitious, Art considers this strategy necessary to achieve key US interests: preventing an attack on the homeland, the emergence of great-power Eurasian wars, and maintaining access to resources.

  • Brooks, Stephen, and William Wohlforth. America Abroad: The United States’ Global Role in the 21st Century. New York: Oxford University Press, 2016.

    In this key book that is part of an influential debate over the future of American grand strategy, Brooks and Wohlforth take issue with the proponents of retrenchment and underline that, through its alliances and military presence, the United States still provides security and stability in the world’s key regions. Withdrawing would be more costly for American security and economic interests than remaining in Europa, Asia, and the Persian Gulf.

  • Dueck, Colin. Reluctant Crusaders: Power, Culture, and Change in American Grand Strategy. Princeton, NY: Princeton University Press, 2008.

    Dueck argues that US grand strategy is shaped by two opposing tendencies: first, by classical liberal assumptions among US policymakers to define American goals in unusually idealistic, expansive, and global terms, and second, by their preference for “limited liability.” Dueck shows these contradictory tendencies in US grand strategy through case studies of three key strategic periods (after World War I, during World War II, and during the Cold War).

  • Kreps, Sarah Elizabeth. Coalitions of Convenience: United States Military Interventions after the Cold War. Oxford: Oxford University Press, 2011.

    DOI: 10.1093/acprof:oso/9780199753796.001.0001

    In this insightful book, Kreps examines why the United States would work with others when it could mostly go it alone, through a study of US interventions during the post–Cold War years. Her answer is that operating multilaterally confers legitimacy upon US preferences, and allows it to partially pass off the costs of these operations.

  • Layne, Christopher. “From Preponderance to Offshore Balancing: America’s Future Grand Strategy.” International Security 22.1 (1997): 86–124.

    DOI: 10.1162/isec.22.1.86

    A key piece in the early post–Cold War literature on the need for the United States to pull back from its Cold War alliances: Layne argues that the United States should instead move toward a grand strategy of offshore balancing without permanent alliances, and intervene only when concrete threats emerge.

  • Layne, Christopher. The Peace of Illusions: American Grand Strategy from 1940 to the Present. Ithaca, NY: Cornell University Press, 2006.

    In this tightly argued book, Layne shows that neither offensive nor defensive realism can sufficiently explain why the United States pursued a grand strategy of “extra-regional hegemony,” though it possesses abundant security through the “stopping power of water.” He argues instead that US policymakers were consistently motivated by “open door” thinking, where the United States could not be secure until the rest of the world also consisted of liberal, free-market democracies.

  • Posen, Barry R. Restraint: A New Foundation for U.S. Grand Strategy. Ithaca, NY: Cornell University Press, 2014.

    A definitive post-Iraq statement on the costs and risks of “liberal hegemony,” in which Posen contends that a limited grand strategy of “restraint” would diminish the costs and risks for the United States. Specifically, Posen argues, that the end of the American presence in Europe, the Persian Gulf, and Asia to maintain US alliances creates avoidable costs and risks for the United States.

  • Walt, Stephen M. “Alliances in a Unipolar World.” World Politics 61.1 (2009): 86–120.

    DOI: 10.1017/S0043887109000045

    Walt discusses the theoretical implications of American unipolarity on the behavior of allies. This is a highly useful piece that takes the existing scholarship on alliances and reviews it in light of the unique structural condition of unipolarity.

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