Triggers of State-Led Mass Killing

Abstract Why do states initiate mass killing campaigns against their civilian populations? What explains the timing of state-led mass killing? Extant research has developed a sophisticated understanding of the general social, political, and economic conditions that elevate a country's risk of state-led mass killing. However, these conditions—which include factors such as regime type and ongoing civil war—are relatively static and cannot explain why violence erupts at a particular point in time, even under high-risk circumstances. In this paper, we explore the specific events that trigger the onset of state-led mass killing. From the scholarly and prevention practice literature, we identify three general categories and seven specific events that are commonly classified as “triggers” of mass killing: changes in armed conflict conditions (government battle losses, rebel civilian killing, and conflict spillover), civilian mobilization (violent and nonviolent protests), and direct threats to leadership integrity (attempted and successful coups). Using the new statistical technique of event coincidence analysis, we evaluate whether, how, and under what conditions these events systematically precipitate mass killings across all countries from 1989 to 2017. Our findings show that government battlefield losses and coups are the most powerful triggers, and that triggering effects are heightened in the context of autocracy, low rule of law, and high levels of ongoing political instability.