Dynamics of Secession
I study the dynamics of secession with a particular emphasis on the international and domestic causes of secessionist conflict over time. I have published several books on this topic including my 2021 book Secession and the Sovereignty Game: Strategy and Tactics for Aspiring Nations (Cornell University Press). In addition, I have published related articles in various journals including International Organization, Nations and Nationalism, and International Studies Review. I have a book coming out in 2025 titled: American Secession: The Folly of a Red State and Blue State Divorce (Oxford University Press).
International System(s) Dataset (ISD)
I am a lead investigator on the International System(s) Dataset (ISD) Project, an effort that critiques the Eurocentric bias in existing datasets and offers a culturally-neutral concept of the state. In version 2 of the ISD, we identified 482 states that existed between 1816 and 2016. Many of these states that constituted dense systems in 19th century Africa and Asia have until now been excluded from data-driven research in international relations. The key articles for this project have been published in International Interactions. We are currently working on version 3 of the dataset with funding from the European Research Council.
Comparative Analysis of State Systems and Orders
I am interested in the organization of the international system with a specific interest in sovereignty and different types of political order over time. Articles in this project have been published in International Theory, the European Journal of International Relations, and International Studies Quarterly. I have a co-authored book (with Charles Butcher) coming out in 2025 titled: Before Colonization: Nonwestern States and Systems in the Nineteenth Century (Columbia University Press).
Global Patterns in Interstate and Intrastate War Since 1750
Understanding the causes and frequency of war is a central mission in the field of international relations. In this project I research three important questions: (1) Has the frequency of war declined over time? (2) Are some historical regions more peaceful than others? (3) Has interstate war declined historically while intrastate war has increased? I address these problems by complementing the International System(s) Dataset with detailed historical data on conflicts for all states since 1750. This project is funded by an NSF-SAP grant.