Book Project
Peer-reviewed Journal Articles
Working Papers and Manuscripts Under Review
Manuscripts in Progress
Book Project: Unruly Friends: Grand Strategy and Strategic Incoherence in Military Alliances
When a great power attempts to check a rival, why do its allies sometimes reconcile their military capabilities with its grand strategy and sometimes appear reluctant or unable to do so? Over the decades, numerous scholars, policymakers, and pundits have come to believe that they understand the sources of strategic incoherence in military alliances. The conventional wisdom—i.e., the “collective goods theory” of alliance security—holds that states have chronic temptations to free-ride on the preponderant ally’s military efforts. To the extent the leading power overcommits resources towards confronting the adversary, its allies will have few incentives to revise their military postures in line with its strategic aims. If this logic is correct, the chief explanation for why a great power like the United States often finds it difficult to achieve strategic coherence in its alliance relationships lies in its own excesses. Once it dials back its security commitments, so the argument goes, allies will finally pull their own weight.
I argue that this conventional wisdom is wrong. Strategic coherence in military alliances is not uniformly conditioned by the generosity of the leading power’s security commitments. Instead, my theory highlights the interaction between the leading power’s grand strategy and the military vulnerability of its allies. Leading powers need allies to bring specific kinds and amounts of military capabilities to the table in order to effectively implement their preferred grand strategies. However, adopting the “appropriate” capabilities is often prohibitively difficult for allies because it requires them to take on awful risks to their fundamental security interests. Doing so may, in particular, trigger unbearably costly countermeasures from the adversary or create otherwise avoidable deficiencies in their military competitiveness. Developing these insights, I argue that strategic incoherence is especially likely when (1) the leading power tries to “outsource” military capabilities to an ally that is highly vulnerable to military predation, or alternatively when (2) its grand strategy is predicated on “insourcing” military capabilities while limiting those of a relatively invulnerable ally.
Using detailed case studies of the United States’ Cold War alliances with France and West Germany, the Soviet Union’s alliances with China and Cuba, Great Britain’s alliances in the early 20th century, and America’s East Asian alliances in the post-Cold War period, I identify the remarkably demanding conditions under which alliances in the modern era have achieved strategic coherence. This effort draws heavily on archival material and, for the contemporary East Asian cases, semi-structured interviews with senior Japanese and South Korean policymakers. In each case, I also show that strategic coherence had nontrivial implications for the alliance’s military performance and political longevity.
Peer-reviewed Journal Articles
“More than a Number: Aging Leaders in International Politics,” International Studies Quarterly 67, no. 1 (March 2023): 1-15 (with Austin Carson).
“Punishment and Politicization in the International Human Rights Regime,” American Political Science Review 116, no. 2 (May 2022): 385-402 (with Rochelle Terman).
“Regional Security Cooperation against Hegemonic Threats: Theory and Evidence from France and West Germany (1945-1965),” European Journal of International Security 7, no. 2 (May 2022): 143-162.
“The Geopolitical Consequences of COVID-19: Assessing Hawkish Mass Opinion in China,” Political Science Quarterly 136, no. 4 (Winter 2021): 641-665 (with D.G. Kim and Sichen Li).
Working Papers and Manuscripts Under Review
Contact me at joshua.byun@bc.edu if you would like to read any of these manuscripts.
“Under No Circumstances? Culture, Preferences, and Chinese Views on the Use of Nuclear Weapons.” With Changwook Ju (Revise & Resubmit, International Studies Quarterly)
The idea of using nuclear weapons to kill noncombatants is said to evoke strong moral opprobrium among millions of individuals across the globe, such that national leaders should be constrained from using the weapons even when such a decision would be strategically sensible. Classical area scholarship and recent survey evidence suggest that this “nuclear taboo” is strong among the Chinese public, buttressed by culturally-grounded preferences for moderation in warfare. Drawing on findings in cultural sociology and American political behavior, we argue that previous studies likely mislead on the extent to which ordinary Chinese citizens might oppose the use of nuclear weapons in a real military clash, primarily due to a failure to distinguish baseline preferences for nuclear non-use from the willingness to approve governmental decisions to use these weapons. Results from an original survey experiment fielded in mainland China show that most individuals who personally dislike the idea of using nuclear weapons are nonetheless willing to support their leaders’ decision to do so. Our study contributes systematic knowledge about the nuclear attitudes harbored by the citizens of the world’s most populous nuclear power and highlights the value of harnessing interdisciplinary insights to inform the research agenda on the nuclear taboo.
“The Paradox of Nuclear Sharing: U.S. Grand Strategy in NATO’s Nuclear Age” (Under review).
Modern great powers have sometimes turned to “nuclear sharing” as a strategy to bolster the military position of smaller allies against formidable adversaries while minimizing the costs of doing so. Under what conditions will the allies successfully adopt the capabilities prescribed by this ambitious strategy? I argue that nuclear sharing is likely to fail when extended to highly vulnerable allies—i.e., those that possess meager power resources and are geographically proximate to the adversary—precisely because it promises a significant power shift in their favor. Substantive nuclear sharing takes time to materialize, giving the adversary incentives to take forceful measures to arrest its neighbor’s militarization before losing the option altogether. Paradoxically, then, nuclear sharing is unlikely to succeed when extended to allies that ostensibly stand to gain most from it. By extension, a strategy of “nuclear monopoly” will produce opposite outcomes: while vulnerable allies will moderate their military postures accordingly, relatively invulnerable allies are likely to adopt independent capabilities that defy the leading power’s strategic priorities. Primary-source evidence from U.S. nuclear strategy in Cold War NATO offers powerful support for these claims. My findings offer lessons for contemporary debates on the nuclear dimensions of U.S. grand strategy and alliance policies.
“Stuck Onshore: Explaining the U.S. Failure to Retrench from Europe during the Early Cold War” (Working paper).
A growing number of scholars and policymakers are showing interest in a grand strategy that calls on the United States to retrench from key global regions while devolving the burden of checking the expansion of hegemonic aspirants to local allies. I highlight the military vulnerability of allies as a neglected variable that can compromise the leading power’s efforts to phase out of an “onshore” military role. The regional great-power adversary is unlikely to sit idle while a weaker neighbor converts its material resources into new military capabilities with the leading power’s sponsorship; it will be tempted to forcefully nip the neighbor’s militarization in the bud. Insofar as allies are sensitive to the risks of incurring costly preventive aggression, they have incentives to undermine the leading power’s efforts to build up their combined military strength as a substitute for the forces it has deployed to the region. I trace the process by which U.S. plans to retrench from Europe were frustrated in the first decade of the Cold War, finding powerful support for my argument. My findings have important implications for the debate on whether the United States might be able to pursue an orderly military withdrawal from Europe and East Asia.
“Unruly Friends: Grand Strategy and Strategic Incoherence in Soviet Alliances” (Working paper).
When a great power attempts to check a rival, why do its allies sometimes reconcile their military capabilities with its grand strategy and sometimes appear reluctant or unable to do so? Against conventional wisdom, I argue that a leading great power’s failure to achieve “strategic coherence” in its military alliances cannot be uniformly attributed to the generosity of its security commitments. Instead, strategic coherence is shaped by the interaction between the leading power’s grand strategy and the military vulnerability of its allies. If the leading power implements an outsourcing grand strategy, strategic incoherence will ensue in relations with allies that are highly vulnerable to military predation while coherence obtains with allies that are relatively invulnerable. By contrast, if the leading power adopts an insourcing grand strategy, strategic incoherence will obtain with the relatively invulnerable allies and coherence with highly vulnerable allies. Evidence from primary material and a rich historiography of the Soviet Union’s relations with China and Cuba offers powerful support for these arguments. My findings suggest that the alliances of leading powers in the 21st century will be attended by radically different patterns of strategic coherence and incoherence depending on what their grand strategy asks allies to do militarily.
“Remember Kabul? Reputation, Strategic Contexts, and American Credibility after the Afghanistan Withdrawal.” With D.G. Kim and Jiyoung Ko (Under review).
The United States’ 2021 withdrawal from Afghanistan sparked heated debate about the credibility of its alliance commitments around the world. Many assume that reputations informed by America’s past behavior in the one region will hurt its future credibility elsewhere. However, some argue that foreign observers discount America’s actions in other regions as an indicator of its credibility as an ally and instead privilege factors specific to the immediate strategic context, such as the military resources the United States can presently bring to bear in their region. We test these competing claims with multi-country survey experiments, assessing how information about the Afghan withdrawal impacts widespread perceptions of American credibility in the United States, South Korea, and China. We identify a striking disjuncture: although Americans tend to believe that the abandonment decision in Afghanistan will hurt their country’s credibility in East Asia, no such effect is found in South Korea and China. In fact, information about the withdrawal increases confidence about American security commitments among East Asian respondents when coupled with the message that the decision will enable Washington to concentrate additional military capabilities in their region. Our findings help adjudicate debates related to the broader strategic implications of the Afghanistan withdrawal.
Manuscripts in Progress
“‘A Fair Background to Show its Strength’: Hiroshima, Nagasaki, and the Lethal Debut of Atomic Weaponry.” With Austin Carson.
“Truncated Occupation and Political Violence in the Postbellum American South.” With Hyunku Kwon.
“Emotional Substrates of Hawkish Mass Opinion.” With D.G. Kim and Nicholas Campbell-Seremetis.
Joshua Byun 