Under conditions of guerrilla conflict, mass indiscriminate violence has been shown to effectively starve a guerrilla of its support. Consequently, counter-guerrilla mass violence is concentrated within territories where a guerrilla is dominant. However, in roughly 40 percent of mass violence episodes (e.g., Rwanda and Cambodia), the violence was aimed at populations within areas of secure territorial control. These episodes have therefore been explained by attributing ideological preferences to leaders or as unique cases only. I argue that leaders adopt mass indiscriminate violence against outgroups to consolidate power under conditions of elite rivalry. The violence serves two main goals. First, it helps build coalitions with constituencies that gain from violence; and second, it targets rival factions indirectly by forcing local security officials to facilitate or oppose the violence. The violence thereby provides rival supporters with an exit option, provides the regime with information on rival supporters’ private loyalties, and undermines rivals’ abilities to mount an effective resistance. These rivals can ultimately be purged from the regime. Based on newly collected original data on elite purges and on the type of mass indiscriminate violence for the years 1950 to 2004, I show that this type of mass violence, which I call “genocidal consolidation,” is intimately connected to authoritarian consolidation.

Many theories of international relations assume that public opinion exerts a powerful effect on foreign policy in democracies. Previous research, based on observational data, has reached conflicting conclusions about this foundational assumption. We use experiments to examine two mechanisms—responsiveness and selection—through which opinion could shape decisions about the use of military force. We tested responsiveness by asking members of the Israeli parliament to consider a crisis in which we randomized information about public opinion. Parliamentarians were more willing to use military force when the public was in favor and believed that contravening public opinion would entail heavy political costs. We tested selection by asking citizens in Israel and the US to evaluate parties/candidates, which varied randomly on many dimensions. In both countries, security policy proved as electorally significant as economic and religious policy, and far more consequential than nonpolicy considerations such as gender, race, and experience. Overall, our experiments in two important democracies imply that citizens can affect policy by incentivizing incumbents and shaping who gets elected.

The current scholarly literature on the international mediation of civil wars draws predominantly on a rationalist-materialist perspective. This perspective suggests that the ticket to mediation success is the material manipulation of the bargaining environment by third parties with a high degree of economic and military resources. I argue that legitimacy also determines outcomes of mediation because if a mediator has legitimacy, it can continue to look for a mutually satisfactory outcome and try to pull the conflict parties toward compliance. I show that legitimacy matters by systematically comparing the effectiveness of African and non-African third parties. African third parties are typically considered ineffective because of a low degree of economic and military capacity. However, they effectively mediate civil wars in Africa because of a high degree of legitimacy, which is a result of a strong conviction within the African society of states that African mediation is the most desirable type in conflicts there. Drawing on data from the Uppsala Conflict Data Program supplemented with unique data, which together cover all mediation efforts in Africa between 1960 and 2017, I find quantitative evidence supporting the effectiveness of African third parties. Compared to non-African ones, African third parties are far more likely to conclude negotiated settlements that are more likely to be durable. African third parties are especially effective if the conflict parties are highly committed to the African solutions norm. Theoretically, this study deviates from much of the literature that puts forward solely rationalist-materialist explanations of mediation success. By bringing legitimacy to the forefront, this article supplements the current mediation literature that emphasizes material sources of power and ignores social structures.

How do migrants decide when to leave? Conventional wisdom is that violence and economic deprivation force migrants to leave their homes. However, long-standing problems of violence and poverty often cannot explain sudden spikes in migration. We study the timing of migration decisions in the critical case of Syrian and Iraqi migration to Europe using an original survey and embedded experiment, as well as interviews, focus groups, and Internet search data. We find that violence and poverty lead individuals to invest in learning about the migration environment. Political shifts in receiving countries then can unleash migratory flows. The findings underscore the need for further research on what migrants know about law and politics, when policy changes create and end migrant waves, and whether politicians anticipate migratory responses when crafting policy.

One likely effect of the COVID-19 pandemic will be an increased focus on health diplomacy, a topic that has rarely been taken up by international relations scholars. After reviewing existing literature on health diplomacy, I argue for the utility of distinguishing states’ aims from their practices of health diplomacy in advancing our understanding of when states engage in health diplomacy with a bilateral, regional, or global scope. The recent history of twenty-first century infectious disease outbreaks suggests a possible move away from health diplomacy with global participation. COVID-19 provides numerous examples, from widespread criticism of the World Health Organization to increased bilateral health aid and the creation of a regional vaccine initiative. As pandemics become more frequent, however, more localized health diplomacy is likely to be less effective, given the necessity of global mitigation and containment.

Do peacekeepers protect civilians in civil conflict? Securing civilian safety is a key objective of contemporary peacekeeping missions, yet whether these efforts actually make a difference on the ground is widely debated in large part because of intractable endogeneity concerns and selection bias. To overcome these issues, we use an instrumental variables design, leveraging exogenous variation in the rotation of African members of the United Nations Security Council and looking at its effects on African civil wars. We show that states that wield more power send more peacekeepers to their preferred locations, and that these peacekeepers in turn help to protect civilians. We thus demonstrate the robustness of many existing results to a plausible identification strategy and present a method that can also be applied to other diverse settings in international relations.

The COVID-19 pandemic presents an opportunity to refocus scholarly attention on the politics of crisis. Crises that abruptly upend political and economic relations are important and increasing in frequency. However, the division of international relations into international political economy (IPE) and international security has contributed to the relative neglect of non-militarized crises like pandemics. Crises are defined by threat, uncertainty, and time pressure: understanding them requires a careful examination of how these variables affect political and economic outcomes. Drawing on often disparate literatures on finance, energy and climate change, natural disasters, pandemics, and violent conflict, I propose a broad research program around the politics of crisis, focusing on puzzles related to causes, responses, and transformations.

This article contributes to an understanding of why autocrats have accepted the jurisdiction of the International Criminal Court. Leveraging their ability to obstruct their own prosecution, autocrats have traded off the risk of unwanted prosecutions against the deterrent threat that prosecutions pose to political rivals and patrons of their enemies conspiring to oust them. The risk of unwanted prosecutions and the court's deterrent threat both arise because ICC prosecutions credibly communicate guilt for international crimes to capital-disbursing democracies, which may, insofar as possible, use leader-specific economic statecraft to prevent the administration of foreign states by those whom the court signals are guilty of international crimes. Analysis using fixed effects and matching shows that a greater reliance on capital publicly financed by democracies increased the probability that a state accepted the court's jurisdiction only when it was an autocracy (1998–2017). ICC jurisdiction also lengthened the tenure of autocrats and reduced the severity of civil conflict in autocracies.

What explains variation in individual preferences for foreign economic engagement? Although a large and growing literature addresses that question, little research examines how partner countries affect public opinion on policies such as trade, foreign aid, and investment. We construct a new theory arguing that political side-taking by outside powers shapes individuals’ support for engaging economically with those countries. We test the theory using original surveys in the United States and Tunisia. In both cases, the potential partner country's side-taking in the partisan politics of the respondents’ country dramatically shapes support for foreign economic relations. As the rise of new aid donors, investors, and trade partners creates new choices in economic partners, our theory and findings are critical to understanding mass preferences about open economic engagement.

How do international observers decide whether to criticize or condone electoral fraud in a country? We argue that this decision depends on the identity of the victims of electoral fraud. A monitoring organization is more likely to overlook fraud committed against groups that are deemed dangerous by its sponsor. Based on this insight, we hypothesize that in the post-Cold War era election monitors are more tolerant of fraud against Islamic challengers, especially when Islamic movements are perceived as a threat to political stability. In support of our hypothesis, we find that outside monitors are more likely to endorse an election in countries with an Islamic opposition party and an ongoing Islamist terrorist campaign. Furthermore, we find that the effect is driven by Western monitoring organizations and becomes stronger after the September 11 attacks. Our findings provide a simple yet powerful insight: the calculus of outside observers depends not only on who they wish to see in power, but also who they want to keep from power.

Since trade must cross borders, to what extent do border walls affect trade flows? We argue that border walls can reduce trade flows. Even if the objective is to only stem illicit flows, border walls heighten “border effects” that can also inhibit legal cross-border flows. Using a gravity model of trade that reflects recent developments in both economic theory and econometrics, we find that the creation of a wall is associated with a reduction in legal trade flows between neighboring countries. We provide a battery of evidence that suggests this reduction is not simply a function of worsening bilateral relations. Our findings have implications for understanding how governments have taken measures to assert sovereign control of their borders in an age of increasing economic globalization.

A wave of recent research challenges the role of regime type in international relations. One striking takeaway is that democratic and autocratic leaders can often achieve similar levels of domestic constraint, which in many issue areas results in similar international outcomes—leading many to question traditional views of democracies as distinctive in their international relations. In this review essay, we use recent contributions in the field to build what we call a “malleable constraints” framework, in which all governments have an institutionally defined default level of domestic audience constraint that is generally higher in democracies, but leaders maintain some agency within these institutions and can strategically increase their exposure to or insulation from this constraint. Using this framework, we argue that regime type is still a crucial differentiator in international affairs even if, as recent studies suggest, democratic and autocratic leaders can sometimes be similarly constrained by domestic audiences and thus achieve similar international outcomes. This framework helps reconcile many competing claims in recent scholarship, including the puzzle of why autocracies do not strategically increase domestic audience constraint more often. Just because autocracies can engage audience constraints and democracies can escape them does not mean that they can do so with equal ease, frequency, or risk.

Contemporary studies of conflict have adopted approaches that minimize the importance of negotiation during war or treat it as a constant and mechanical activity. This is strongly related to the lack of systematic data that track and illustrate the complex nature of wartime diplomacy. I address these issues by creating and exploring a new daily-level data set of negotiations in all interstate wars from 1816 to the present. I find strong indications that post-1945 wars feature more frequent negotiations and that these negotiations are far less predictive of war termination. Evidence suggests that increased international pressures for peace and stability after World War II, especially emanating from nuclear weapons and international alliances, account for this trend. These original data and insights establish a dynamic research agenda that enables a more policy-relevant study of conflict management, highlights a historical angle to conflict resolution, and speaks to the utility of viewing diplomacy as an essential dimension to understanding war.

Recent empirical evidence suggests that Chinese development finance may be particularly prone to elite capture and patronage spending. If aid ends up in the pockets of political elites and their ethno-regional networks, this may exacerbate ethnic grievances and contribute to ethnic mobilization. In this research note I examine whether Chinese development projects make local ethnic identities more salient in African partner countries. A new geo-referenced data set on the subnational allocation of Chinese development finance projects to Africa is geographically matched with survey data for 50,520 respondents from eleven African countries. The identification strategy compares sites where a Chinese project was under implementation at the time of the interview to sites where a Chinese project will appear subsequently. The empirical results suggest that living near an ongoing Chinese project makes ethnic identities more salient. There is no indication of an equivalent pattern when considering other donors’ development projects.

This essay uses COVID-19 to illuminate the sacrificial practices of the liberal international order as woven through the concepts of humanitarian governance, moral economy, triage, and sacrifice. The concept of a sacrificial international order calls attention to how all international orders have their share of sacrifices—and this includes liberal international orders. International orders can be distinguished by the selection mechanisms used to identify the sacrifices and the meanings attached to them. I call attention to how liberal international orders often rely on markets as a selection mechanism and interpret these deaths as part of progress. Following critical contributions to the study of neoliberalism that show how markets shape the ethics of “giving life” and “letting die,” I illuminate these processes through four concepts: humanitarian governance and the claim that the highest moral principle is saving lives and relieving suffering; moral economy that regulates who has access to basic subsistence goods during periods of crisis; triage, which considers how to prioritize whose lives are valued; and whether all deaths count as sacrifices or whether they are better understood as “those who can be killed.” I conclude by discussing how COVID-19 conjures hierarchies of humanity ignored by the liberal international order and challenges the discipline to consider the sacrifices in world order.

A key piece of conventional wisdom among scholars of modern armed conflict is that collateral damage is often strategically costly in war. Yet most combatants already know this and take actions after mistakes—most prominently, the distribution of “condolence payments” to civilian victims—in order to mitigate these costs. Do these payments work? This question is important not only for policymakers but also for deeper theoretical debates about how civilians respond to combatant signals in war. To examine these issues, I use micro-level conflict event data on 4,046 condolence payments made by Coalition forces to civilian victims during the Iraq War from 2004 to 2008, matching it with corresponding data on collateral damage and insurgent violence. The results of this analysis reveal that post-harm compensation does significantly diminish local rates of insurgent violence, and that this is true across different types of payments (cash handouts or in-kind assistance). Ultimately, these patterns can be best explained by a rationalist mechanism in which civilians update their beliefs about violent events based on new information about combatants’ wartime intentions. The results thus provide a compelling strategic rationale for combatants to compensate their victims in war, and suggest that civilians are not blinded to new information about conflict dynamics by their preexisting biases.

Terrorists attack civilian targets but there is variation in how many civilians they kill. Terrorists may deliberately harm civilians, or they may adopt a less bloody approach, demolishing businesses, transit systems, and other civilian property while employing tactics to avert civilian casualties. One such tactic is to warn civilians before an attack, allowing them to flee the area. With warnings as an example, this study considers why terrorists might adopt casualty-aversion tactics. An analysis of 12,235 bombings by 131 terrorist groups in the years 1970 to 2016 finds that warnings are most common when terrorists fight democracies and when they lack territorial strongholds. Ideological factors such as religion are not significant predictors of warnings. These findings suggest a need to revisit the claim that religion incentivizes indiscriminate terrorism. They also suggest a strategic logic behind casualty-aversion tactics. Terrorists fighting democracies may spare civilians to appear legitimate in citizens’ eyes. Terrorists without strongholds may spare civilians because they rely on the state's population for support. At first glance, my findings appear to contradict civil war literature arguing that militants with strongholds use violence more discriminately. However, terrorism occurs in areas of state control. Militants with strongholds can use indiscriminate terrorism against state-governed civilians without alienating their own supporters elsewhere.

The customary prescription for handling “problems without passports” is to work through international intergovernmental organizations (IGOs), act collectively for humanity's future, and build up specialized knowledge. But around the world, patterns from the initial months of the COVID-19 pandemic defied the prescription. IGOs were blamed, narrow or short-term interests were prioritized, and divided reactions to experts were on display. International Relations (IR) scholarship helps explain why: (1) research on bureaucracy and institutional design examines the challenge of making IGOs accountable to member-states but also insulated from them; (2) research on delegation and socialization explores commonplace problems involving time-inconsistency and credible commitments; and (3) research on epistemic communities and anti-elitism describes the rationale and fears of permitting public policy to be guided by unelected experts. The initial months of the COVID-19 pandemic reflect how the world can look when it lacks resolute leadership to overcome commonplace aversions to IGOs, to broader or longer-term interests, and to experts. Yet while IR scholarship makes sense of these patterns, it does not say enough about why resolute leadership wanes, or what to do about IGO performance when it does. Answers to such questions are crucial not only for recovering from the COVID-19 crisis, but for dealing with whatever global crises lie ahead.