Research

Publications

1. “Winners and Losers in U.S.-China Trade Disputes: A Dynamic Compositional Analysis of Multinational Corporations’ Market Penetration” (with Yoo Sun Jung). 2024. Social Science Quarterly 105(4): 980-995. [Ungated] [Publisher site] [Appendix] [Replication]

2. “Remittances, Terrorism, and Democracy” (with Casey Crisman-Cox). 2024. Conflict Management and Peace Science 41(5): 598-622. [Ungated] [Publisher site] [Appendix] [Replication]

3. “Signaling Restraints: International Engagement and Rebel Groups’ Commitment to International Law” (with Hyeran Jo, Joshua Alley, and Soren Jordan). 2021. International Interactions 47(5): 928-954. [Ungated] [Publisher site] [Appendix] [Replication]

Working Papers

1. Appeal to the Public: Why Leaders Make Public Threats. [Draft]
   • [Abstract]

     Why do leaders go public? During an armed crisis, leaders have strong concerns about the public's evaluation of their conflict behavior. I argue that leaders issue public threats, especially ambiguous ones, to address these concerns. Using public statements, leaders can provide domestic audiences with information on their progress in the crisis, reframe the issues at stake, and make a justification for the decisions they have made or will make further. Moreover, leaders strategically embrace ambiguity within their public statements to satisfy broader audiences with heterogeneous preferences over how to handle the crisis. I test my argument with a novel measure of the US leaders' perceived public concerns during the Vietnam War. Applying supervised learning methods to the declassified White House documents from 1961 to 1976, I measure the US decision-makers' time-varying concerns about the public's evaluation of their foreign policy. The analysis of the US foreign policy documents finds that leaders are more likely to issue public threats, and they make these threats more ambiguous as they perceive the public to be more concerned about leaders' policy competence in Vietnam. These findings imply that the presence of domestic audiences could undermine the credibility of a state's public threats.
2. A Doubly Robust Difference-in-Differences Estimator for Causal Inference with Time-Series Cross-Sectional Data. (with Thomas Chadefaux)
   • [Abstract]

     This paper addresses the challenge of deriving robust causal effects from time-series cross-sectional (TSCS) data. The task is especially complex with multiple treatment status changes, heterogeneous treatment effects, and unobserved time-varying confounders, leading to increased bias and reduced efficiency. Here, we introduce a novel difference-in-differences (DID) estimator to assess the average treatment effect on the treated (ATT), building upon the principles of doubly robust DID estimation. Our approach involves creating matched sets by pairing each treated observation with control observations from different groups that share an identical treatment history. We employ a combination of propensity score and outcome regression methods, incorporating machine learning algorithms with cross-validation, to calculate both immediate and long-term ATTs. Our simulation and empirical analyses demonstrate the estimator's semi-parametric efficiency and resilience to incorrect model specifications. We also introduce an open-source software package for these methods' implementation.
3. Following the Flag vs. Business as Usual: Sectoral Heterogeneity in How Multinationals Respond to Political Tensions. (with Yoo Sun Jung)
   • [Abstract]

     Do deteriorating political relations between states disrupt economic relations? The existing literature suggests that political tensions discourage foreign direct investment (FDI) due to increased political risks. Our study examines how the impact of political tensions on FDI varies across industries. We propose that the preemption risk posed by competitors creates a threshold where tensions no longer affect economic relations, allowing investors to continue with `business as usual.' When increased political risk arising from political tensions outweighs the threat of preemption in the market, multinationals are likely to reduce their investment. However, when the risk of losing market share to competitors is significant, firms are less likely to `follow the flag,' thereby mitigating the negative impact of political tensions. Using project-level greenfield FDI data from the fDi Markets database, we find that political tensions between home and host countries reduce investment in less fixed-asset-intensive industries, but have little to no impact on high fixed-asset industries. Our results suggest that in a highly competitive globalized world, investments in strategically important industries like primary, energy, and resources are largely insulated from political frictions between states.
4. Strategic Interventions to Protect Civilians: Assessing the Efficacy of Mediation, Peacekeeping, and Sanctions. (with Lisa Hultman and Hyeran Jo)
   • [Abstract]

     What saves lives in civil conflicts around the world? International actors frequently employ a variety of measures such as mediation, sanctions, and peacekeeping to protect civilians from violence by non-state actors. But which of these measures is the most effective for reducing violence? We hypothesize that the feasibility and efficacy of these interventions hinge on rebel strength. Mediation works better when rebels are weak, whereas peacekeeping and sanctions are more effective when rebels are strong. This is because they work through different mechanisms and will be selected strategically. We test our theory with monthly data of rebel civilian killing between 1989 and 2019. Using a difference-in-differences estimator enhanced by matching methods, the strategic selection into the different intervention types is accounted for before estimating their efficacy. Our work contributes to the literature on global security governance, providing an integrative view of international measures, beyond the analysis of each measure separately.
5. Militant Violence Against Civilians, International Interventions, and Unintended Consequences. (with Hyeran Jo, Niels Appeldorn, and Yewon Kwon)
   • [Abstract]

     Militant violence against civilians surpassed state violence against civilians at the turn of the 20th and early 21st century. The international community has tried various intervention measures to reduce militant violence against civilians around the world, including mediation, peacekeeping, and sanctions. Under what conditions might unintended consequences arise? We argue and show international actions can increase the militant civilian killing when interventions accentuate the distributional impacts on militant factions, aggravating existing militant group fragmentation, militant rivalry, and/or collusion between militants and the host government. Using the interrupted time-series intervention analysis, we find support for our arguments from the analysis of militant violence in the Democratic Republic of Congo. Our findings have implications for external intervention in internal conflicts, highlighting the limits and opportunities for global security governance in the age of backlash against the liberal international order.

Selected Works in Progress

1. Multinational Firms and the Impact of Trade Disputes on Investment Decisions. (with Erica Owen and Yoo Sun Jung )
   • [Abstract]

     The rise of global value chains (GVCs) is reshaping the political economy of trade in several ways, including the politics of trade disputes. Trade disputes affect access to markets and suppliers in ways that are likely to influence investment decisions. Indeed, recent work examines how multinationals influence the initiation and duration of disputes. Yet we know little about how multinationals respond to trade frictions in a world of GVCs. We offer a theory of international trade and investment that interrelates trade, FDI, global production, and GVC participation. We argue that trade disputes can actually lead to greater inward FDI in respondent countries because a (resolved) trade dispute signals lower barriers to trade. This hurts domestic producers in the respondent and creates opportunities for multinationals in the complainant country. However, we expect that the effect of trade disputes will depend on how and to what extent the industry integrates into GVCs. In particular, we expect the impact of a dispute to be greater where there are more backward linkages, that is, in industries that rely on imported inputs. We use data on dyad-industry level greenfield FDI from FDI markets between 2003 and 2015 to test our hypotheses.
2. Justice v. The Terminator: Militants and Policy Interactions in Conflict Zones. (With Beth Simmons and Hyeran Jo)
   • [Abstract]

     Can international justice intervention in conflict zones reduce militant violence against civilians? We argue that international justice can operate by altering viable options for certain militant leaders, consequently affecting the commission of international crimes such as civilian killing. The key expectation is that international justice can contribute to the reduction of militant violence when the prosecutorial efforts reduce the support system available to rebel groups, especially those who are more vulnerable to such disruptions. We test our arguments with a cross section of all situations in which the International Criminal Court (ICC) has issued warrants. We follow up with an overtime analysis of Democratic Republic of Congo (DRC), the site of a long conflict history, multiple and diverse rebel groups, and multiple cases in which arrest warrants were issued by the ICC. ICC warrants have modest effects that seem to work through the vulnerability of groups to constriction in their support portfolios, which in turn encourage them to moderate their violence toward civilians. Our results point to the modest power of an arrest warrant to provide normatively relevant information that limits groups’ support – some so much so that they strategically choose to moderate violence toward civilians.
3. Optimizing Thresholds in Machine Learning for Improved Regression Analysis. (with Jong Woo Jeong)
   • [Abstract]

     The growing trend among political scientists to apply machine learning algorithms for measuring theoretical concepts, and the subsequent use of these measures in regression analysis, highlights the importance of the algorithms' performance in determining measurement accuracy and regression estimator robustness. However, there has been a lack of comprehensive discussion among political scientists on the impact of imperfect machine learning predictions on regression estimators. This article addresses this gap by providing a practical guide for achieving the best measurement quality when applying machine learning algorithms to measuring latent variables. We particularly focus on identifying the most suitable threshold values for classifying the concept of interest. In binary predictions, where machine learning is widely used, such threshold settings are key in determining measurement accuracy and avoiding attenuation biases in regression estimates, especially in the context of complicated time-series cross-sectional data. Our simulations and empirical analyses show that the proposed method significantly reduces biases by adjusting threshold values for classification.
4. Power structure, domestic constraints, and selective targeting.
   • [Abstract]

     Previous studies of interstate conflict suggest that leaders who are accountable to domestic audiences have an incentive to target weaker countries in militarized disputes due to the fear of post-defeat domestic punishment. I argue that the effect of domestic audiences on leaders' decisions vary with the international power structure. Under a bipolar structure, minor powers face great uncertainty about dispute outcomes because fierce superpower competition undermines the importance of the balance of power between the disputants. Moreover, the shared concerns about the total war between the two superpowers lead the minor powers to be ambiguous about the superpowers' commitments about support. The dispute outcome uncertainty discourages the leaders with domestic audiences from making risky decisions, whereas it encourages the relatively unconstrained leaders to adopt reckless policies. The analyses of the initiation of militarized disputes between 1946 and 2010 show that regime types with domestic audiences are less likely than personalist regimes to initiate militarized conflicts against stronger opponents in the Cold War period. However, the difference between each non-personalist regime and personalist regime decreases following the end of superpower competition. This finding implies the diminished role of domestic audiences in constraining state leaders during the post-Cold War era.