“Threat perception” is frequently invoked as a causal variable in theories of international relations and foreign policy decision making. Yet haphazard conceptualization and untested psychological assumptions leave its effects poorly understood. In this article, I propose a unified solution to these two related problems: taking the brain into account. I first show that this approach solves the conceptualization problem by generating two distinct concepts that generalize across existing theories, align with plain language, and are associated with specific brain-level processes: threat-as-danger perception (subjectively apprehending danger from any source) and threat-as-signal perception (detecting a statement of the intention to harm). Because both types of perception occur in the brain, large-scale neuroimaging data capturing these processes offer a way to empirically test some of the psychological assumptions embedded in IR theories. I conduct two such tests using assumptions from the literatures on conflict decision making (“harms are costs”) and on coercion (“intentions are inscrutable”). Based on an original analysis of fifteen coordinate-based meta-analyses comprising 500+ studies and 11,000+ subjects, I conclude that these assumptions are inconsistent with the cumulative evidence about how the brain responds to threats of either kind. Further, I show that brain-level data illuminate aspects of threat perception's impact on behavior that have not yet been integrated into IR theory. Advancing the study of threat perception thus requires a microfoundational approach that builds from what we know about the brain.

How do states as social actors cope with stigma-induced status anxiety? I propose the concept of “stigma shifting” as a way in which status-anxious states overcompensate for their stigma-induced inferiority and reaffirm their place in the world: by seeking identification with higher-status states and differentiation from lower-status states. In identifying with the desired group of states, stigmatized states engage in approval-seeking behavior and reaffirm their in-group status in areas where they feel discredited. In differentiating themselves from the undesired group, stigmatized states engage in distinction-seeking behavior, claiming their superiority over this “lesser” group in areas that gave rise to their status anxiety in the first place. Stigma shifting, in other words, allows a stigmatized state to take the role of a stigmatizer. To demonstrate the concept's depth and analytical utility, I draw on the case of East Asia in three disparate issue areas: colonial redress, nuclear disaster, and international order making. Japan, stigmatized in all three areas, has reaffirmed its status by shifting the stigma onto its significant but “lesser” others: China and Korea. Ultimately, stigma shifting solidifies status hierarchies in the world—not just the hierarchy as represented by the “Western” dominance of international society but also the regional hierarchies of the non-Western world.

Why do rebel splinter groups emerge during peace processes, and who chooses to defect? Since Colombia's landmark peace agreement with the FARC in 2016, roughly half of the territory once controlled by the group has seen a resurgence of rebel activity by FARC splinter groups. I argue that the FARC's return to arms is a case of “middle-out fragmentation,” whereby opportunities for profit induce mid- or low-ranking rebel commanders to establish splinter groups. In Colombia, I argue that profits from the cocaine trade incentivized local-level FARC officers to defect from the peace agreement and allowed them to rapidly mobilize viable splinter groups. I offer several lines of evidence for this argument. I first construct a chronology of splinter group formation, which demonstrates that mid- and low-level commanders, rather than high-level commanders, were the key drivers of fragmentation. Second, I show that splinter groups emerged in areas where opportunities for profit were greatest. Among areas previously controlled by the FARC, those with coca cultivation prior to the peace agreement were up to thirty-seven percentage points more likely to see splinter groups emerge by 2020 than areas without significant production. Using soil and weather conditions to instrument for coca cultivation produces similar results. Further, I use a novel measure of how critical each municipality is to drug trafficking to show that areas that are theoretically most important for drug trafficking are also more likely to see FARC resurgence. I also address competing explanations related to state capacity, terrain, and popular support for the rebels. These findings highlight an important challenge to peacebuilding: satisfying the political demands of rebel leadership is a necessary but insufficient component of peace agreements in cases where opportunities for profit motivate fragmentation from the middle out.

While many scholars expect people's ideological orientations to drive their beliefs regarding the legitimacy of international organizations (IOs), research has found surprisingly limited support for this common assumption. In this article we resolve this puzzle by introducing the perceived ideological profile of IOs as a critical factor shaping the relationship between ideological orientation and such beliefs. Theoretically, we argue that citizens accord IOs greater legitimacy when they perceive these organizations as ideologically more congruent with their own orientations. Empirically, we evaluate this expectation by combining observational and experimental analyses of new survey evidence from four countries: Brazil, Germany, Indonesia, and the United States. We find that citizens indeed perceive IOs as having particular ideological profiles and that those perceptions systematically moderate the relationship between people's ideological orientations and their sense of IOs’ legitimacy. These findings suggest that political ideology is a more powerful driver of legitimacy beliefs in global governance than previously understood.

Conventional wisdom holds that open, collaborative, and transparent organizations are innovative. But some of the most radical innovations—satellites, lithium-iodine batteries, the internet—were conceived by small, secretive teams in national security agencies. Are these organizations more innovative because of their secrecy, or in spite of it? We study a principal–agent model of public-sector innovation. We give research teams a secret option and a public option during the initial testing and prototyping phase. Secrecy helps advance high-risk, high-reward projects through the early phase via a cost-passing mechanism. In open institutions, managers will not approve pilot research into high-risk, high-reward ideas for fear of political costs. Researchers exploit secrecy to conduct pilot research at a higher personal cost to generate evidence that their project is viable and win their manager's approval. Contrary to standard principal–agent findings, we show that researchers may exploit secrecy even if their preferences are perfectly aligned with their manager's, and that managers do not monitor researchers even if monitoring is costless and perfect. We illustrate our theory with two cases from the early Cold War: the CIA's attempt to master mind control (MKULTRA) and the origins of the reconnaissance satellite (CORONA). We contribute to the political application of principal–agent theory and studies of national security innovation, emerging technologies, democratic oversight, the Sino–American technology debate, and great power competition.

Across countries and over time, support for economic globalization is strongest among individuals with the highest levels of education. Yet despite long-lasting debates on the sources of this correlation, reliable evidence that isolates the causal effect of education from the nonrandom selection of individuals into education is lacking. To address this fundamental issue, I exploit compulsory-schooling reforms that increased the minimum school-leaving age in eighteen countries. Employing a fuzzy regression discontinuity design, I find that the reform-induced added years of education substantially and durably increased support for trade liberalization. And using new data on the content of school curricula, I find that the effect of schooling largely stems from instilling tolerance and pluralism in citizens and reducing the perceived cultural threat of globalization. In contrast, there is little evidence that the effect of schooling reflects the distributive consequences of international trade, separating globalization winners and losers.

Are publics in great power democracies more likely to approve of foreign armed combatants that comply with international humanitarian law (IHL)? There is a wealth of evidence that armed combatants with an incentive to seek the support of outside compliance constituencies are more likely to adhere to IHL. Yet a key mechanism underlying these claims—that people in great power democracies are more likely to support armed combatants that comply with IHL—has not been directly tested. We address this question using a series of experiments embedded in nationally representative surveys conducted in three democracies that have frequently been involved in foreign interventions: France, the United Kingdom, and the United States. We find that belligerents—both governments and rebels—that comply with the laws of war are significantly more likely to garner support from publics in likely intervening countries compared to those who do not comply. In all three countries, compliance with international law caused greater approval of armed combatants as well as greater support for economic or military intervention (although support for military intervention remained relatively low in the treatment groups). This lends support to arguments that, to the extent combatants seek support from outside audiences, this can serve as a mechanism by which international law constrains armed combat.

Why might female leaders of democratic countries commit more money, equipment, soldiers, and other resources to interstate conflicts than male leaders? We argue that gender bias in the process of democratic election helps explain this behavior. Since running for office is generally more costly for women than for men, only women who place a higher value on winning competitions will choose to run. After election, they also devote more resources to pursuing victory in conflict situations. To provide microfoundational evidence for this claim, we analyze data from an online laboratory game featuring real-time group play in which participants chose to run for election, conducted a simple campaign, and represented their group in a contest game if elected. Women with a higher nonmonetary value to winning were more likely to self-select into candidacy, and when victorious, they spent more resources on intergroup contests than male elected leaders. The data suggest that electoral selection plays an important role in observed differences between male and female leaders in the real world.