Militant Group Alliances and Rivalries

The Militant Group Alliances and Rivalries (MGAR) Database provides reliable information for a systematic understanding of the scope, causes, and consequences of violent non-state actor relationships. The database includes year-by-year data for hundreds of groups, including their material, financial, operational, and training relationships with each other and other entities, including states. Using the dyad-year as the unit of analysis, the data capture the dynamic quality of these relationships which range from operational alliances to open rivalry and conflict.

This project was made possible by the support of the Minerva Research Initiative project “Terrorist Alliances: Causes, Dynamics, and Consequences” ONR Award Number: N000141210966.

Download Codebook and Data



Blair, Christopher W., Erica Chenoweth, Michael C. Horowitz, Evan Perkoski, and Philip B.K. Potter. “Honor among Thieves: Understanding Rhetorical and Material Cooperation among Violent Nonstate Actors.” International Organization, 2021, 1–40. (Please cite this article when you use the data).

Other MGAR Publications

Blair, Christopher, Michael C Horowitz, and Philip Potter. “Leadership Targeting and Militant Alliance Breakdown.” The Journal of Politics, 2021.

Horowitz, Michael C., and Philip B. Potter. “Allying to Kill: Terrorist Intergroup Cooperation and the Consequences for Lethality.” Journal of Conflict Resolution 58, no. 2 (2013): 199–225.


Meet the Team

Christopher Blair

Christopher Blair is a doctoral candidate in the Department of Political Science at the University of Pennsylvania, and a graduate affiliate of the Penn Identity & Conflict Lab. His work spans international relations and comparative politics, with a substantive focus on the political economy of conflict and migration. He specifically studies counterinsurgency, forced displacement, and public opinion on foreign policy. Chris holds an M.A. in Political Science from the University of Pennsylvania, and a B.A. with Highest Distinction in Politics and History from the University of Virginia, where he also participated in the Distinguished Majors Program.


Erica Chenoweth

Dr. Erica Chenoweth is the Frank Stanton Professor of the First Amendment at Harvard Kennedy School and a Susan S. and Kenneth L. Wallach Professor at the Radcliffe Institute for Advanced Studies at Harvard University. Chenoweth’s research focuses on political violence and its alternatives. Their book Why Civil Resistance Works(Columbia, 2011), with Maria J. Stephan, won the 2013 Grawemeyer Award for Ideas Improving World Order and the 2012 best book award from the American Political Science Association. Foreign Policy magazine has ranked Chenoweth among the Top 100 Global Thinkers of 2013 for their efforts to promote the empirical study of nonviolent resistance.


Michael C. Horowitz

Michael C. Horowitz is Director of Perry World House and Richard Perry Professor at the University of Pennsylvania. He is the author of The Diffusion of Military Power: Causes and Consequences for International Politics, and the co-author of Why Leaders Fight. He won the 2017 Karl Deutsch Award given by the International Studies Association for early career contributions to the fields of international relations and peace research. He has published in a wide array of peer reviewed journals and popular outlets. Professor Horowitz received his Ph.D. in Government from Harvard University and his B.A. in political science from Emory University.


Evan Perkoski

Dr. Evan Perkoski is an Assistant Professor of Political Science at the University of Connecticut and a Nonresident Fellow at the Krulak Center for Innovation and Creativity at the Marine Corps University. Specializing in the study of international relations, his research explores the inner working and strategic choices of armed groups, the dynamics of violent and nonviolent uprisings, and the evolution of cyber warfare. His first book – Divided, not Conquered: How Rebels Fracture and Splinters Behave – is forthcoming with Oxford University Press.



Philip B.K. Potter

Dr. Philip Potter is an Associate Professor and Director of Graduate Studies in the Department of Politics and Founding Director of the National Security Policy Center in the Frank Batten School of Leadership and Public Policy at the University of Virginia. He is a University Expert with the National Ground Intelligence Center. Dr. Potter is on the editorial boards of the Journal of Politics and the Journal of Global Security Studies and is an Associate Principal Investigator for Time-Sharing Experiments in the Social Sciences (TESS). He has been a fellow at the Modern War Institute at West Point, Harvard, and the University of Pennsylvania.




The MGAR database was supported by the Department of Defense through the Minerva Initiative.