How Terrorism Spreads: Emulation and the Diffusion of Ethnic and Ethnoreligious Terrorism

Previous research on the causes of domestic terrorism has tended to focus on domestic determinants. Although this approach can be helpful to understand many causes of terrorism, it implicitly disregards how the tactical choices made by similar nonstate actors elsewhere influence a group’s decision to resort to terrorist tactics. This study argues that the adoption of terrorism among ethnic and ethnoreligious groups results from a process of conditional emulation. Groups are more likely to emulate the terrorist choice of others with whom they are connected by shared political grievances and spatial networks. The theory is tested on a new and original group-level data set of ethnic and ethnoreligious terrorism (1970 to 2009) using geospatial analysis and spatial econometric models. The results provide strong support for the hypothesized mechanism leading to the diffusion of terrorism and suggest that emulation—more than domestic and contextual factors—substantially influences dissidents’ tactic choice.