Scott Wolford and Yuji Masumura. Forthcoming. Shifting Power, Interstate War, and Domestic Politics. American Journal of Political Science.
Abstract
We analyze a model in which shifting power undermines rising foreign states’ commitments to the status quo, and domestic leaders can’t credibly communicate the scale of averted power shifts after preventive war. Domestic publics prefer war only when power shifts are large, but preventive war leaves them unobservable, giving leaders incentives to lie ex post to avoid political punishment. When publics are ex ante skeptical over the value of prevention and war outcomes are middling, the probabilities of war and political punishment, as well as public skepticism over the value of war, all increase in war outcomes. We show that public strategies of punishing military failures are uniquely unsuccessful at discouraging undesirable preventive war, and the same conditions that encourage preventive war undermine its political benefits. We also use the model to explain why Japan’s leaders failed to convince the public of preventive success against Russia in 1905.
Yuji Masumura and Atsushi Tago. 2023. Micro-foundations of the Quest for Status: Testing Self-Status Perception and the Multilateral Use of Force, Foreign Policy AnalysisArticle, Appendix, DataAbstract
Research on status in international relations has expanded in the last few decades. The key empirical studies suggest that status concern generates an incentive for initiating international conflicts since unilateral military engagement is believed to increase the status of a country. We concur with this argument. However, a further study should be conducted to find if "multilateral" military engagement can change status perceptions and therefore be related to international politics over status. The test is important since the multilateral use of force is distinct from the unilateral use of force in its theoretical background and its connotation in world politics. In our experiment conducted in Japan, we treat the information on the multilateral use of force, and examine whether variations of the treatment information change people's perception over their country's international status. The results show that participation in a multilateral use of force increases and an early departure from the multilateral mission out of casualty concerns decreases their country's status perception. Also, we successfully identify that the people who have a high social dominance orientation (SDO) trait are more susceptible to such information.
Working Papers
Arming, Rising, and a Screening Effect of Alliances. Presented at ISA 2025.
Abstract
I analyze a formal model under which a growing state decides to arm but this creates an incentive for preventive war due to the fear of hidden revisionism. Then, I investigate how alliances alter this preventive war motive. The model reveals a screening effect of alliances. Alliances make arming more informative by changing the value and purpose of arming, and this screens the otherwise hidden intention of a rising protégé. In this screening effect, alliances solve a different information problem from other existing theories, and fully committed alliances can both constrain a protégé and deter an aggressor at the same time. Two implications are empirically tested: (a) alliances decrease the possibility of preventive war and (b) the costs of internal arming decrease military expenditure when coupled with alliances.
A Theory of Cost-Sharing Negotiations of Military Alliances. Presented at APSA 2024 and Texas Triangle 2025. slidepaperAbstract
The literature on military alliances suggests that alliances can deter aggression through costly signaling. In reality, however, protégés often share substantive alliance costs, which makes alliances cheaper for a patron and should derail the signaling. Why do protégés do that? To explain this gap, I develop a formal model in which allied countries negotiate cost-sharing under the shadow of international crisis and domestic politics. The model identifies two means by which cost-sharing negotiations sustain peace. First, successful negotiations keep a patron’s involvement by reducing the alliance costs when the patron is not strongly committed. Second, a large cost-sharing demand makes the negotiations fail, but it signals the patron’s commitment and panders to domestic isolationism at the same time. Empirical records of the US-Japan alliance in 1978 and 2019 are explained through these mechanisms.
Trapping a Friend: How do Arms Transfers Constrain Alliance Partners? (with Yasuki Kudo), Under Review, Presented at MPSA 2024 and will be presented at APSA 2025
Abstract
Why does the US transfer more arms to stronger partners than weaker ones? We analyze models in which arms transfers have two different consequences -deterrence and constraint- and a hegemon attempts to send the optimal level of arms to maintain the status quo. We find that the key to explaining the pattern of the US arms transfers is constraining motivation. The hegemon sends arms to partners who are more likely to defeat their adversaries. Supplied arms reduce the likelihood of the recipients' initiation of military actions since the hegemon retains control over the use of supplied arms in a dispute. Statistical analyses of US arms transfers, coupled with a case study of the US-Iran relationship in the Johnson administration, support these expectations. This research offers a systematic explanation of how the US pursues its primary foreign policy objective -the maintenance of world order- through arms transfers.
A Tale of Experiment on Two-isms of International Relations: A Study in Japan (with Masanori Kikuchi and Atsushi Tago), Under Review
Abstract
In International Relations (IR), the famous isms such as Realism and Liberalism still prevail. As the debate over those isms began to abate in the 1990s, some textbooks departed from teaching them, but as an information short-cut, the isms seem to have an impact on how people understand international relations. Those isms could affect the people to support a particular type of foreign policies. Our experiment, by using two kinds of framing on Realism and Liberalism respectively, uncovers how the isms can change the general public's perception over key international policies. The evidence shows that the people support unilateralism in national security motivated economic sanction cases if they are primed for Realism and see the policy would increase a country’s international status. By contrast, the study shows that the people are not really affected by Liberalism framing and being neutral for multilateral policy choices. The study is an example of showing the power of Realism and helps our understanding over how the people formulate their distinctive worldviews on international relations.
The Power of the President of the UN Security Council, Presented at ISA 2023 and APSA 2023
Abstract
How do weak countries achieve their diplomatic goals in international organizations? I investigate this question in the context of the UN Security Council and its president. I argue that the elected UNSC members alter collective UNSC decisions through the UNSC presidency. By leveraging the alphabetical-order rotation of the president and applying the keyword-assisted topic model to the resolutions from 1992 to 2016, I analyze the effect of the president on the UNSC resolutions. The results affirm the strong influence of the president. Resolutions about (nuclear) weapons are likely to be adopted when the president’s preference is close to the United States, whereas ceasefire-related resolutions are likely to be passed when the president’s preference is different from the United States, possibly because these countries try to lock in the Council’s involvement. Also, resolutions related to humanitarianism are likely to be adopted when the president has a democratic regime. This article reveals how weak countries are empowered by rules and how they shape the course of power politics.
Work in Progress
New Leader, State Visit, and General Deterrence (with Muhib Rahman) (To be presented at MPSA 2025)
Diamond, L. (2019). Ill Winds: Saving Democracy from Russian Rage, Chinese Ambition, and American Complacency. Penguin Books. Translated into Japanese by Maiko Ichihara, Yuji Masumura, Takuto Tokairin, Atsushi Sugii, and Ryohei Suzuki [Publisher]