Curriculum Vitae








Modeling the Coevolution of International and Domestic Institutions: Alliances, Democracy, and the Complex Path to Peace
Journal of Peace Research 53 (3): 424-441, 2016.

(PDF) (Replication File)

While much previous research has examined the relationship between interstate military alliances and the structure of domestic regimes, existing findings point in contradictory directions. Some have argued that democracies attract each other as alliance partners, and thereby generate international peace as a consequence of their domestic regime type, while others have argued that the causal relationship is reversed, and that international pacification creates the necessary space for international alliances and domestic democratization. To disentangle this difficult empirical relationship, this article presents an empirically grounded simulation model of the dynamic coevolution of interstate military alliances, international conflict, and domestic democratization, demonstrating a statistical approach which accounts both for the complex interdependencies generated by coevolving multiplex networks of interstate ties and for their reciprocal influence on the coevolution of domestic political regimes, over the period 1920-2000. The results show that international institutions and domestic institutions are mutually constituted, with both 'selection' effects and 'influence' effects operating simultaneously. In particular, the evidence indicates that states with similar regimes are more prone to ally with each other, mutually democratic dyads are less inclined to engage in militarized disputes, and states that form international alliances with democratic partners are more likely to develop domestic democratic institutions. Tests of out-of-sample predictive accuracy, across multidecade prediction windows, further demonstrate that the coevolutionary model consistently outperforms specifications that ignore coevolutionary effects, in predicting subsequent patterns of military alliances, military conflict, and domestic democratization.


Explosive Connections? Mass Media, Social Media, and the Geography of Collective Violence in African States
Journal of Peace Research 52 (3): 297-311, 2015.

(PDF) (Press Coverage) (Replication File)

Growing evidence indicates that the diffusion of information and communication technologies (ICTs) can substantially alter the contours of collective violence in developing nations. However, empirical investigations of such effects have generally been hampered by an inability to systematically measure geographic variation in ICT penetration, across multiple technologies and multiple countries. In this paper, I show that geo-referenced household surveys can be used to estimate sub-national differences in the spatial reach of radio and cellular communications infrastructures in 24 African states. By combining these estimates with geo-referenced measures of the location of disaggregated events of collective violence, I show that there are important differences between centralized 'mass' communication technologies - such as radios - that foster vertical linkages between state and society, and decentralized 'social' communication technologies - such as cell phones - that foster horizontal linkages between the members of a society. The evidence demonstrates that the geographic reach of mass media penetration generates substantial pacifying effects, while the reach of social media penetration generates substantial increases in collective violence, especially in areas lacking access to mass media infrastructure. I argue that these findings are consistent with a theory of ICT effects which focuses on the strengthening and weakening of economies of scale in the marketplace of ideas.


Explaining Violent Intra-Ethnic Conflict: Group Fragmentation in the Shadow of State Power (with Kevin Troy)
Journal of Conflict Resolution 59 (3): 484-509, 2015.

(PDF) (Replication File)

Despite significant advances in the disaggregation of the study of civil conflict and inter-ethnic violence, intra-ethnic violence remains understudied. In this paper, we present the first systematic, cross-national analysis of the conditions that promote violent, fragmentary conflict within politically active ethnic minorities. We propose a model of intra-ethnic conflict in which collective violence is produced by the interaction between sub-group entrepreneurs and the suppressive actions of the state. This two-level model predicts a curvilinear relationship between the relative size of an ethnic minority and its probability of experiencing large-scale intra-ethnic conflict. Additional hypotheses based on the proposed causal mechanism are also posited. These hypotheses are tested with data drawn from a global sample of politically active ethnic minorities, for the period 1990 - 2006, using a combination of parametric and semi-parametric regression techniques. The results strongly confirm the predicted curvilinear relationship, while also demonstrating that the specific shape of this relationship shifts in predictable ways under varying social and political contexts.


Not by the Sword Alone: Soft Power, Mass Media, and the Production of State Sovereignty
International Organization 68 (1): 111-141, 2014.

(PDF) (Replication File)

Scholars of civil conflict have long recognized the importance of state strength in the suppression of nascent insurgencies. However, previous empirical investigations have generally focused on the material and coercive dimensions of state power, obscuring the critical role played by the generation of widespread voluntary compliance through processes of political communication, i.e. the production of soft power. In contrast, in this paper I focus on a factor – mass communication technology – that can enhance state capacity only by strengthening the state's ability to broadly and publicly disseminate political messages. I argue that the enhanced capacities for large-scale normative influence generated by mass communication technologies can be expected to produce substantial barriers to the mobilization of militarized challenges to state rule, by strengthening economies of scale in the marketplace of ideas. Utilizing newly compiled cross-national data on mass media accessibility in the post-World War II period, I show that densely constituted mass media systems dramatically reduce the probability of large-scale civil violence, thereby providing new evidence for the fundamental importance of non-material state capacities in the suppression of internal armed conflicts.


Testing Clausewitz: Nationalism, Mass Mobilization, and the Severity of War (with Lars-Erik Cederman and Didier Sornette)
International Organization 65 (4): 605-638, 2011
(PDF) (Replication File)

Drawing on Clausewitz’ classical theory, we argue that the emergence of mass nationalism following the French Revolution profoundly altered the nature of the units constituting the interstate system, thereby transforming the conduct of interstate warfare. To validate these assertions -- and thus to test Clausewitz -- we rely on quantitative evidence at the macro-level, with a particular focus on the global distribution of interstate war sizes, measured in terms of battle deaths, over the past five centuries. Relying on Extreme Value Theory, we demonstrate that temporal discontinuities in the shapes of such tail distributions can be used to draw inferences about the nature of the mechanisms underlying the bloodiest events in world history. This approach allows us to show that the interstate system experienced a fundamental shift in the mechanisms underlying the production of war sizes; a shift which can be dated with remarkable precision to the years 1770-1810, and which resulted in a systematic increase in war severity. These same tools also allow us to rule out a number of alternative explanations for this shift (including changes in population sizes and changes in weapons technology), while providing evidence for a specific account of war severity rooted in the mobilizational capacities of states.


The Geometry of Security: Modeling Interstate Alliances as Evolving Networks
Journal of Peace Research 47 (6): 697-709, 2010.
(PDF) (Replication File)

In this article it is argued that interstate alliances function as public costly signals of state intentions to cooperate militarily, and as such, they should be expected to influence state expectations within dyads, between dyads, and across time. Accurate statistical modeling of interstate military alliances thus requires that researchers escape the assumption of independent units of observation, which is built into most of the statistical tools currently used by international relations scholars, as such models can be expected to produce unbiased parameter estimates in this domain only if the decisions to create and dissolve interstate alliances are formulated in isolated dyadic bubbles. The use of stochastic actor-oriented models, combined with Markov simulations of network evolution, is shown to be a productive alternative method of modeling interstate alliances, which allows the researcher to avoid the assumption of dyadic independence by incorporating theory-driven assumptions about patterns of extra-dyadic interdependence directly into the functional form of the statistical model. The results demonstrate that triadic patterns of amity and enmity exercise powerful influence over the selection of alliance partners and the evolution of the global alliance network. The results also show that failure to incorporate patterns of extra-dyadic interdependence into our statistical models of interstate alliance decisions is likely to result in biased parameter estimates.


When Preferences and Commitments Collide: The Effect of Relative Partisan Shifts on International Treaty Compliance (with Joseph M. Grieco and Christopher F. Gelpi)
International Organization
63 (2): 341-355, 2009.
(PDF) (Replication File)

In this paper, we demonstrate that changes in the partisan orientation of a country's executive branch influence the likelihood that the government of that country with comply with international legal commitments aimed at integration of capital markets. We argue that relative shifts in executive partisan orientation, whether towards the left or towards the right, represent important shifts in "national preferences" that have heretofore been absent from statistical models of treaty compliance. Using a matching estimator combined with a genetic algorithm to maximize balance in our sample, we show that the causal impact of a state signing Article VIII of the IMF Articles of Agreement is conditioned by right-to-left shifts in partisan orientation. The evidence indicates that such preference changes reduce the constraining effects of Article VIII, but also indicates that Article VIII continues to exercise significant causal effects even in the face of relative shifts in executive partisan orientation.


Working Papers

The Physics of Statecraft: Technology, Terrain, and the Territorialization of Modern States (with Lars-Erik Cederman and Sebastian Schutte)

While variation in the power and size of states has long been recognized as one of the central drivers of geopolitical behavior, few studies have directly addressed the question of how and why different states came to be the sizes they did. The most prominent formal contributions to this question, based in a logic of voluntary optimization, fail to account for some of the most fundamental patterns observed in empirical data on state sizes, including the fact that territorial sizes are consistently lognormally distributed. In contrast, we develop an ecological model of coercive competition, which seeks to capture both the positive feedback dynamics inherent in states' pursuit of territorial expansion, and the physical constraints of projecting power over long distances. Moreover, we show that the empirical predictions derived from this model are in strong agreement, both qualitatively and quantitatively, with real distributions of state sizes observed over the period 1500 AD to 1998 AD.


Mapping State Reach: Territorial Segregation, Cultural Penetration, and the Ethnic Topography of Insurgency (with Sebastian Schutte)

While previous research has indicated that non-coercive forms of state influence can play a critical role the in prevention of civil conflict, the evidence for such claims has generally been based on national aggregates, obscuring the substantial variation in state capacity that exists within countries. In this paper we demonstrate that correspondence between geographic variation in the reach of broadcast communication technologies, and geographic variation in the topology of ethnic settlement patterns, exercises profound influence over the generation of anti-state violence. Using newly compiled data on the settlement locations of politically relevant ethnic groups, and geo-coded indicators of the costs of mass media penetration, we conduct a global disaggregated analysis of the relationship between domestic soft power and civil conflict mobilization at the level of specific ethnic groups. The results reveal that groups living in peripheral regions, especially those with terrain that generates difficulties for the deployment of mass communication infrastructure, face a dramatically heightened likelihood of violent rebellion.


Domestic Audiences and International Conflict: Bargaining in the Shadow of Mass Mediated Publics

Much of the contemporary literature on interstate conflict highlights the importance of signaling processes between potential and actual adversaries.  The assumption frequently made in such work is that so-called "audience costs" allow leaders to more credibly signal their intentions by heightening the stakes leaders face in diverging from their stated positions.  However, this mechanism assumes the presence of a particular kind of collective audience: a mass audience capable of jointly receiving messages and capable of generating coordinated responses to such messages.  I argue that such mass mediated publics are not naturally occurring characteristics of the interstate system, but rather are constituted by particular domestic communicative structures.  Moreover, those structures are not constants, but instead vary considerably over time and space.  Using cross-national time-series data for the period 1945-1998, I demonstrate that the constraints produced by differing levels of media freedom and media density lead to significant differences in interstate conflict behavior, including the likelihood of dispute initiation and reciprocation.  I further show that the “democratic peace” effect is actually conditional on domestic communicative structures, operating only in the presence of sufficiently free and sufficiently dense mass media networks.

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