The Burden-Sharing Dilemma: Coercive Diplomacy in US Alliance Politics

By Brian D. Blankenship

The Burden-Sharing Dilemma examines the conditions under which the United States is willing and able to pressure its allies to assume more responsibility for their own defense. The United States has a mixed track record of encouraging allied burden-sharing—while it has succeeded or failed in some cases, it has declined to do so at all in others. This variation, Brian D. Blankenship argues, is because the United States tailors its burden-sharing pressure in accordance with two competing priorities: conserving its own resources and preserving influence in its alliances. Although burden-sharing enables great power patrons like the United States to lower alliance costs, it also empowers allies to resist patron influence.

Blankenship identifies three factors that determine the severity of this burden-sharing dilemma and how it is managed: the latent military power of allies, the shared external threat environment, and the level of a patron's resource constraints. Through case studies of US alliances formed during the Cold War, he shows that a patron can mitigate the dilemma by combining assurances of protection with threats of abandonment and by exercising discretion in its burden-sharing pressure.

Blankenship's findings dismantle assumptions that burden-sharing is always desirable but difficult to obtain. Patrons, as the book reveals, can in fact be reluctant to seek burden-sharing, and attempts to pass defense costs to allies can often be successful. At a time when skepticism of alliance benefits remains high and global power shifts threaten longstanding pacts, The Burden-Sharing Dilemma recalls and reconceives the value of burden-sharing and alliances.

• Language: English
• Publisher: Cornell University Press
• Release date: Nov 15, 2023
• ISBN: 9781501772498

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Cover: The Burden-Sharing, Coercive Diplomacy in US Alliance Politics by Brian D. Blankenship

The Burden-Sharing Dilemma

Coercive Diplomacy in US Alliance Politics

BRIAN D. BLANKENSHIP

Cornell University Press

Ithaca and London

Contents

Acknowledgments

List of Abbreviations

Introduction

1. The Strategic Logic of Coercive Burden-Sharing

2. A Legitimate Role in the Defense of the Alliance, but on a Leash

3. Between Scylla and Charybdis

4. They Live at Our Sufferance

5. Is Iceland Blackmailing Us?

Conclusion

Appendix

Notes

References

Index

Acknowledgments

I am enormously thankful to have had so many mentors, colleagues, friends, and family that helped me along the journey to completing this book, one way or another. I owe particular thanks to my mentors during my undergraduate studies at Indiana University and my graduate studies at Columbia University, most notably Richard Betts, Allison Carnegie, Page Fortna, Sumit Ganguly, Robert Jervis, Tonya Putnam, Armando Razo, Dina Spechler, Jack Snyder, Johannes Urpelainen, Gerald Wright, and Keren Yarhi-Milo. I owe a special debt of gratitude to Robert Jervis, whose work and wise counsel has left a lasting impact on my thinking and my research, this book being no exception. I am also extraordinarily grateful for the feedback I received on earlier iterations of the book from my mentors and colleagues during my postdoctoral fellowships at Dartmouth’s Dickey Center for International Understanding and at the Council on Foreign Relations, including Stephen Brooks, Jeffrey Friedman, James Lindsay, Jennifer Lind, Nicholas Miller, Daryl Press, Sheila Smith, Paul Stares, Benjamin Valentino, and William Wohlforth.

Since beginning on the tenure track at the University of Miami, I have had the good fortune of having supportive colleagues who have offered wise advice and feedback on this project and many others, including Cali Curley, Jennifer Connolly, Louise Davidson-Schmich, June Dreyer, Xue Gao, Laura Gomez-Mera, Namhoon Ki, Casey Klofstad, Greg Koger, Costa Pischedda, Mike Touchton, and Joe Uscinski. Outside the University of Miami, I have benefited from my conversations with a number of scholars, including Josh Alley, Jonathan Caverley, Tim Crawford, Mayumi Fukushima, Andres Gannon, James Goldgeier, Dotan Haim, Koji Kagotani, Kelly Matush, Roseanne McManus, Mike Poznansky, Josh Shifrinson, Jennifer Spindel, Katsuya Tsukamoto, and Tristan Volpe. I would also like to extend a special thanks to Tongfi Kim, Alexander Lanoszka, Sara Bjerg Moller, and Paul Poast for participating in my book workshop and offering invaluable feedback—not least of all the suggestion for this book’s title—without which the book would not be what it is today.

This book owes a great debt to the editors at Cornell University Press and the Cornell Studies in Security Affairs series, particularly Michael McGandy, Jacqulyn Teoh, and Stephen Walt, as well as an anonymous reviewer, for their insightful comments on the manuscript and for shepherding it through the process of review and publication. I am grateful as well to the editors and anonymous reviewers at Security Studies, particularly Ron Krebs and Jennifer Erickson, for their feedback on an earlier iteration of the manuscript. I thank Taylor and Francis for granting me permission to adapt material from my article The Price of Protection: Explaining Success and Failure in US Alliance Burden-Sharing Pressure, Security Studies 30, no. 5 (2021): 691–724, available online: http://www.tandfonline.com/10.1080/09636412.2021.2018624. I also thank Oxford University Press for allowing me to adapt material from my article Promises under Pressure: Statements of Reassurance in US Alliances, International Studies Quarterly 64 (2020): 1017–30. This project was made possible in no small part thanks to the generous support I received from the Smith Richardson Foundation and Columbia’s Weatherhead East Asian Institute, in addition to the institutional support I received from Columbia University, Dartmouth’s Dickey Center for International Understanding, the University of Miami, and the Council on Foreign Relations.

Over the years I have been fortunate to have made a number of friends and colleagues who not only have provided insights, feedback, and advice but also, and perhaps even more importantly, have kept me in good spirits: Seung Cho, Ben Denison, Renanah Joyce, Raymond Kuo, Erik Lin-Greenberg, Jeff Lax, Shawn Lonergan, Cullen Nutt, Asli Saygili, and Joon Yang. I owe a debt of gratitude to my friends outside of academia as well for reminding me of life beyond work: Shadman Ahmed, Nathan Berbesque, Alex Brueggman, Spencer Chenhall, Ryan Huffman, Salman Iqbal, Warwick Mannington, Ryan Smith, and Al Wood.

Last but hardly least, I would like to thank my family. My sister, Brooke Blankenship, and my mother, Mary Ellen Blankenship, have been a constant source of support. Without the sacrifices of my parents, I doubt I would have been able to take advantage of the opportunities to advance my education, and this book would not exist. While he was not able to read this book, I have little doubt that my father, Curtis Blankenship, would have kept his copy close to him. Finally, I would like to say a few words of appreciation for my wife, Olivia Warschaw, as well as Nora Warschaw-Alexander, Gary Warschaw, Arpie Meneshian, and Jonah Warschaw, who immediately made me feel like part of the family. Olivia has been the most supportive, loyal partner I could possibly have. I could not have managed the journey without her.

Abbreviations

Introduction

Why Is Burden-Sharing a Contentious Issue in US Alliances?

A recent US president once complained that Washington’s allies do not pay their fair share for defense. Free riders aggravate me, he stated bitterly. You have to pay your fair share.¹

This president was not Donald Trump, who repeatedly made headlines by casting doubt on his willingness to protect US allies unless they made sufficient defense contributions.² Rather, it was his predecessor, Barack Obama. Indeed, Obama’s secretary of defense went so far as to warn US partners that there will be dwindling appetite and patience … to expend increasingly precious funds on behalf of nations that are apparently unwilling to devote the necessary resources … to be serious and capable partners in their own defense.³

Obama and Trump were hardly the first US leaders to solicit greater burden-sharing from US allies. In late 1953, President Eisenhower’s secretary of state John Foster Dulles warned that unless Europe became more self-reliant, the United States would undertake an agonizing reappraisal of basic United States policy toward its commitment to the Continent.⁴ In much the same way, John F. Kennedy threatened to withdraw US troops from West Germany to secure compensation for the costs of stationing them in the country, declaring that we cannot continue to pay for the military protection of Europe while the NATO states are not paying their fair share and [are] living off the ‘fat of the land.’⁵ Across numerous administrations, the need for allied burden-sharing has been a constant refrain in US foreign policy.

But there is striking variation in the success and, in fact, the incidence of US burden-sharing pressure. In some cases, burden-sharing pressure efforts succeed—Jimmy Carter, for instance, persuaded South Korea to increase its defense spending to 6 percent of gross national product when he leveraged the possibility of troop withdrawals.⁶ At other times, they fail—US pressure on the United Kingdom to retain its military presence in Asia during the 1960s amounted to little.⁷ And then there are those cases, perhaps most puzzling of all, where US officials have notably declined to seek greater allied contributions to the common defense. During the early 1970s, for example, the Nixon administration refrained from seeking a substantially greater Japanese military role despite the explicit ambition of the Nixon Doctrine to delegate more responsibility to allies to defend themselves.⁸ Similarly, US policymakers have repeatedly balked at the prospect of a united, independent European defense capability since the end of the Cold War.⁹

This book attempts to understand such variation in burden-sharing within US alliances. It investigates why the United States sometimes puts pressure on its allies to bear more of the collective burden (and sometimes doesn’t) and when these burden-sharing pressures succeed (or don’t). To that end, it advances two central claims. First, US decisions to encourage allied burden-sharing at all are the product of calculations about both the benefits and the risks of greater allied self-reliance. Burden-sharing is useful insofar as it can purchase a similar amount of collective military power at lower US cost. But in some cases—particularly those in which allies have a realistic capability to go their own way—the United States actually prefers that its allies not assume more responsibility for their own defense, since doing so can reduce their dependence on US protection and, by extension, US influence. Second, if the United States elects to encourage allied burden-sharing, its success depends on whether allies fear that it will abandon them. The more credible its threat of abandonment, and the more allies depend on its protection, the more successful it will be.

Each claim challenges strands of conventional wisdom on burden-sharing. The first rethinks the assumption that larger allies disproportionately contribute to collective defense and are always encouraged to do so.¹⁰ I suggest that patrons like the United States actually have good reason not to encourage their largest allies to spend more on defense—namely, to prevent them from becoming too independent. The second claim confronts the notion that the United States’ ability to pressure allies into greater burden-sharing is inherently precluded by its disproportionately great power and vast network of overseas troop deployments. I show that the United States is in fact sometimes able to wield the threat of abandonment to encourage greater burden-sharing even among allies that host a substantial US troop presence. Thus, even though great powers like the United States may be constrained in their ability to solicit allied military contributions, they are far from helpless in doing so. The operative constraint on alliance burden-sharing is in some cases not the United States’ ability to secure it, but simply its willingness to seek it.

What We Know (and Don’t Know) about Burden-Sharing

Burden-sharing refers broadly to actions by which an alliance member contributes to the alliance’s capacity to carry out its objectives. These contributions can take a number of military or nonmilitary forms, such as deploying forces to active conflicts, hosting military bases, providing logistical support, or supplying aid.¹¹ In this book, I focus on burden-sharing in the form of allies’ efforts to provide for their own defense and enhance their own military capabilities.

Burden-sharing is core to the functioning of alliances. By enabling states to pool resources, burden-sharing crucially ensures that alliances can achieve their collective goals, as they are unlikely to succeed in deterring and defeating adversaries unless their members possess sufficient capabilities. A lack of burden-sharing, or free-riding, can cause an alliance to fail to achieve its objectives if the patron is unwilling or unable to contribute enough by itself, and it can create discord in the alliance by generating resentment among members who feel taken advantage of.¹² Burden-sharing additionally facilitates the self-preservation of great powers. Scholars have long argued that overinvesting in military power sows the seeds of great powers’ long-term decline by diverting resources from more productive investments and innovation.¹³ They offer evidence that even financing military spending through debt does not avoid painful fiscal trade-offs, as doing so can cause inflation and contribute to economic crises.¹⁴ These problems are especially challenging in asymmetric alliances between a more powerful great power patron and weaker partners, as the patron’s greater capacity to provide security for the alliance makes it tempting for weaker partners to seek a free ride.¹⁵ Securing allied burden-sharing thus allows a patron to ensure that its commitments do not exceed its resources, and that adversaries can be deterred at a sustainable cost.

The literature on burden-sharing, however, is generally pessimistic about its prospects in asymmetric alliances, largely portraying burden-sharing by smaller allies as an objective that great power patrons seek but have difficulty attaining. This pessimism partly has to do with the predominant view that alliances between great powers and weaker states feature an asymmetric exchange, wherein the former provides security for the alliance while the latter gives up some degree of foreign policy autonomy. From this perspective, the capacity for burden-sharing in asymmetric alliances is limited almost by definition; the great power already tacitly agrees to the costs of providing security in exchange for weaker states’ aligning their foreign policies with its own.¹⁶ Another cause for pessimism has to do with an understanding of alliances based on the logic of public goods, which emphasizes that larger alliance members tend to contribute disproportionately more to collective defense since it is their contributions that ultimately matter most. From this perspective, smaller allies rationally free-ride, and alliances with more members tend to feature more free-riding.¹⁷ Others likewise suggest that the global US military footprint and other assurances of US protection encourage allies to free-ride.¹⁸ Alexander Lanoszka, for instance, suggests that Washington’s efforts to discourage nuclear proliferation forced it to fortify its commitment to allies’ defense, thereby diminishing the United States’ ability to encourage allied burden-sharing.¹⁹

This literature also tends not to focus on allies’ ability to influence each other’s contributions through coercive bargaining. To the extent that they do consider burden-sharing as a bargaining outcome, they adopt, at most, a tacit bargaining framework in which allies’ military expenditures change in response to changes in the patron state’s defense spending.²⁰ But we know very little about what this bargaining process looks like in practice, or about the conditions that encourage states to pressure their partners to contribute more and the factors that lead to success. Indeed, the studies that do approach burden-sharing through a bargaining framework mostly focus on particular cases and do not present a general theory that can systematically explain variation in burden-sharing across time and cases.²¹

These studies thus leave gaps in our understanding of variation in burden-sharing. They cannot fully explain why France withdrew from NATO’s military command in 1966, despite being among NATO’s largest members; why Germany, since the end of the Cold War, has been among NATO’s lowest spenders on defense as a percentage of its gross domestic product (GDP); or why, by contrast, comparably smaller NATO members in the 2010s—notably Estonia, Latvia, Lithuania, and Poland—have punched above their weight. Moreover, they cannot fully explain why allies who hosted many US troops nevertheless spent a great deal on defense. Empirical research on the subject has produced mixed results and does not conclusively show that signals of alliance commitment negatively impact burden-sharing—some studies find that the presence of US troops has a negative effect on burden-sharing, but others find no such effect.²² While there are cases in which US protection almost certainly discouraged allies from making significant efforts toward self-defense—perhaps most famously Japan, whose constitution’s Article 9 imposes restrictions on its military, and Iceland, whose membership in NATO came with the assurance that it would not need to have a military—there are yet other cases in which allies hosting tens or hundreds of thousands of US troops still contributed a great deal to their own security, such as West Germany and South Korea.

Existing literature likewise has difficulty explaining why the United States has in other cases been reluctant to seek more burden-sharing from its partners. In addition to seeking just a modest military contribution from Japan, US officials only grudgingly accepted the need for West German rearmament during the early Cold War so that it could assist NATO in counterbalancing Soviet power in Central Europe.²³ Similarly, US policymakers were lukewarm about European proposals for a more united European defense policy during the 1990s and 2000s, and even the Trump administration balked at proposals for a European defense fund.²⁴

What one is left with, then, are two puzzles. The first is that while in many cases the United States has been able to actively shape its partners’ military contributions—even in seemingly unlikely cases where allies hosted considerable numbers of US troops—other times it has failed to do so. The second is that in some cases the United States has actually preferred that its allies not maximize their military capabilities, even when doing so could have allowed it to conserve its own resources.

The Argument in Brief

These puzzles raise the following question: Under what conditions is the United States willing and able to encourage allied burden-sharing? The answer lies in what I call alliance control theory. Alliance control theory predicts that patrons like the United States will calibrate their burden-sharing pressure toward allies in consideration of three factors—an ally’s latent military potential, the external threat environment, and the patron’s resource constraints. It shows that a substantial amount of variation in asymmetric alliance burden-sharing is the result of bargaining between the patron and its weaker allies.²⁵ Although alliances can discourage allies from investing in their own defense, a patron can mitigate this tendency by combining assurances of support with threats of abandonment. The extent to which the patron’s protection can be made conditional on allies’ burden-sharing efforts, in turn, depends on whether the patron is both willing to ask them to contribute more and able to credibly threaten to abandon them if they do not.

In deciding to seek allied contributions, a patron must balance competing priorities. On the one hand, burden-sharing allows a patron to secure military power for collective defense against shared adversaries without bearing the costs of doing so itself. For this reason, patrons can be expected to encourage allied burden-sharing when the alliance’s external threat environment is severe and when their own resources are constrained. On the other hand, asking allies to shoulder more responsibility for defending themselves reduces both the value of the alliance to them and their dependence on the patron’s protection. As such, patrons are likely to tailor their efforts at securing allied contributions not only to maximize cost savings, but also to minimize the risk of empowering allies to go their own way and exit the alliance. Patrons, in other words, are likely to take a Goldilocks approach to allied burden-sharing. While the smallest allies have little to contribute, and so pose the least risk of defection, larger allies, who have more to contribute, pose the greatest risks, since they have greater potential to fend for themselves outside of the alliance. Counterintuitively, then, it is not the allies who have the greatest potential to provide resources for collective defense that face the most pressure to contribute. Rather, it is moderately sized allies who are strong enough to make meaningful contributions, but not so strong that they can choose to leave the alliance given sufficient investments in defense.

If a patron does choose to seek greater burden-sharing, its success then depends on whether allies fear being abandoned by it. Two factors shape the effectiveness of patron burden-sharing pressure: whether a patron’s threat of abandonment is credible, and how badly allies need protection. A patron can more believably threaten to walk away from its alliances when it faces strains on its resources and pressure to retrench from domestic actors, which constrain its ability to maintain its commitments. Its threat of abandonment is also likely to carry more weight for allies who perceive a greater level of external threat and thus can less easily afford to lose the patron’s protection.

Patrons, in sum, face a burden-sharing dilemma—they must balance discouraging free-riding and encouraging allies to remain loyal to the alliance through a reduction of allies’ incentives and capabilities to act independently.²⁶ Stated differently, patrons in asymmetric alliances must find a trade-off between control—their ability to influence allies’ preferences and persuade them to act in ways that align with their own—and cost-sharing—their ability to reduce the costs of military readiness for themselves and shift those costs onto their partners. Although patrons can never fully overcome this dilemma, they can nevertheless mitigate it by making their protection conditional on allied burden-sharing and manage it by exercising caution in their attempts to secure burden-sharing.

Scope Conditions and Limitations

This book examines coercive burden-sharing efforts that aim at getting allies to assume more responsibility for their own defense by enhancing their own military capabilities. I focus on this form of burden-sharing not only because it is among the most frequently discussed indicators of allied contributions in existing literature, but also because the pool of military power available to an alliance plays a central role in determining the success or failure of an alliance and in shaping the military missions it can successfully carry out.²⁷ Although the book indirectly touches on other forms of burden-sharing insofar as they can substitute for military buildups, it does not aim to explain variation in US efforts to encourage such other forms of burden-sharing. To be sure, the causal processes that drive all forms of burden-sharing are likely to overlap—one might expect fear of abandonment to drive allied contributions in other domains, for example. Yet, the key difference between these forms is the double-edged nature of encouraging allies to enhance their military capabilities; this form of burden-sharing empowers allies to go their own way, whereas others do not. The theory of burden-sharing pressure that this book develops thus accounts only for the unique dilemmas inherent to this form of contribution.

My theory is thus not meant to judge which allies are free-riding or not. Isolating any one form of alliance contribution and using it as the standard by which to judge all members’ contributions risks missing the multitude of other contributions that allies make.²⁸ Some allies are better suited to some contributions than others; larger, wealthier allies, for example, can more effectively supply material resources, while smaller, poorer allies may be limited to making nonmaterial contributions such as military bases. Moreover, allies can elect to contribute to collective defense missions for reasons unrelated to patron pressure.²⁹ This book makes a narrower claim to explain the conditions under which a patron attempts to pressure partners to invest in their own defense and why these attempts succeed or fail.

Additionally, this book looks at burden-sharing in the context of asymmetric alliances, here defined as formal agreements between two or more states in which at least one partner agrees to be involved in case other signatories come under attack, and in which one member (the patron) is significantly more powerful than the others.³⁰ Its empirical content focuses on alliances formed within the bipolar and unipolar systems that emerged after 1945. This period saw an explosion of asymmetric alliances led by the United States or the Soviet Union—a marked difference from the period preceding World War II, during which alliance formation was characterized more by symmetric alliances between great powers within a multipolar system.³¹ The bipolar and unipolar systems of the Cold War and post–Cold War periods thus represent ideal grounds for studying the dynamics of asymmetric alliances. That said, I examine only asymmetric alliances formed by the United States during this period, and not those by the Soviet Union. The coercive nature of Soviet alliances, coupled with these allies’ greater concern with internal rather than external threats, make comparisons across the two alliance blocs difficult.³² Nevertheless, my conclusion discusses the extent to which my findings can shed light on the dynamics of burden-sharing in Soviet alliances.

Focusing on post-1945 US alliances potentially limits the generalizability of this book’s findings in several ways, since there are certain characteristics of the United States and its alliances that are peculiar to them. The first is that the United States and most of its allies are democracies. This detail raises the question of whether US alliances are shaped by the democratic peace, which could mean that US willingness to use threats is particularly constrained by normative affinity between democracies.³³ Yet, this possibility may be moot—many argue that the democratic peace can be attributed more to democracies’ transparency and ability to signal their intentions or to democracies being tougher opponents in wartime rather than to shared norms and values.³⁴ That aside, democratic politics may also shape perceptions of US reliability. The literature on democratic alliance credibility stresses that democratic allies may be more (or less) trustworthy than nondemocratic allies given their transparency, checks and balances, and regular leadership turnover.³⁵ Thus, as a democratic patron, the United States’ willingness and ability to use threats of abandonment may be distinctive.

Second, the United States is geographically remote from the vast majority of its allies (and adversaries), and thus its ability to directly dominate or conquer wayward allies is much less than that of a contiguous, continental power such as the Soviet Union.³⁶ Therefore, assurances of support and threats of abandonment may play a greater role in US alliances than in alliances of coercion in which a patron uses force to keep its allies in line. Moreover, having local partners may be especially important for the United States given the expenses that a geographically remote power must incur to project power, so burden-sharing may be more important in US alliances.³⁷ Its distance from allies might similarly give US threats of abandonment inherent credibility, given the difficulty of projecting power and the margin of safety afforded to it by the Atlantic and Pacific Oceans.³⁸

Third, US security guarantees are underwritten by the United States’ nuclear capabilities. This capacity may reduce the need for conventional forces in the alliance and make allies reluctant to make costly investments in conventional military power.³⁹ Nuclear alliances may thus be tough cases for encouraging allied conventional burden-sharing. Yet, even as the fear of nuclear retaliation may deter large-scale conflict, it may not necessarily reduce—or may even increase—the risk of lower-scale conflicts where the threat of nuclear retaliation is less