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Days of Action or Restraint? How the Islamic Calendar Impacts Violence

  • MICHAEL J. REESE (a1), KEVEN G. RUBY (a1) and ROBERT A. PAPE (a1)


Does the religious calendar promote or suppress political violence in Islamic societies? This study challenges the presumption that the predominant impact of the Islamic calendar is to increase violence, particularly during Ramadan. This study develops a new theory that predicts systematic suppression of violence on important Islamic holidays, those marked by public days off for dedicated celebration. We argue that militant actors anticipate societal disapproval of violence, predictably inducing restraint on these days. We assess our theory using innovative parallel analysis of multiple datasets and qualitative evidence from Islamic insurgencies in Iraq, Afghanistan, and Pakistan from 2004 to 2014. Consistent with our theory, we find that important Islamic holidays witness systematic declines in violence—as much as 41%—and provide evidence that anticipation of societal disapproval is producing these results. Significantly, we find no systematic evidence for surges of violence associated with any Islamic holiday, including Ramadan.


Corresponding author

Michael J. Reese (corresponding author) is Senior Lecturer, Committee on International Relations, 5828 S. University Ave., University of Chicago, Chicago, IL, 60637 (
Keven G. Ruby is Research Director, Chicago Project on Security and Threats, 5828 S. University Ave., University of Chicago, Chicago, IL, 60637 (
Robert A. Pape is Professor, Department of Political Science and Chicago Project on Security and Threats, 5828 S. University Ave., University of Chicago, Chicago, IL, 60637 (


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We thank Nidal Alayasa, Sophia Alice, Nasir Almasri, Vincent Bauer, Jan Box-Steffensmeier, Patrick Brandt, Bear Braumoeller, John Brehm, Bonnie Chan, Li Chen, Mariya Grinberg, Robert Gulotty, Walker Gunning, Isaac Hock, Gentry Jenkins, Morgan Kaplan, Austin Knuppe, Chad Levinson, Charles Lipson, Michael Lopate, Asfandyar Mir, Natasha Murtaza, Paul Poast, Burcu Savun, Yubing Sheng, Duncan Snidal, Jack Snyder, Matthias Staisch, Monica Toft, Felicity Vabulas, Kevin Weng, three anonymous reviewers, and the editors of the APSR for valuable comments. The article benefited from presentations at the Program on International Politics, Economics, & Security (PIPES) at the University of Chicago and the 2014 North American Meeting of the Peace Science Society (International). The authors also gratefully acknowledge the support of the Office of Naval Research (Award N00014-12-1-0035) and the Carnegie Corporation of New York. All errors remain solely our own.



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Days of Action or Restraint? How the Islamic Calendar Impacts Violence

  • MICHAEL J. REESE (a1), KEVEN G. RUBY (a1) and ROBERT A. PAPE (a1)


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