Leadership decapitation : volume and intensity of terrorist attacks

What is the effect of leadership decapitation—the targeted killing or capture of a leader—on the violence levels of terrorist groups? Strong evidence has yet to emerge, as existing literature examines its effect on group degradation, measured as the duration of group existence post-decapitation. However, this outcome variable does not allow us to fully explore the question. Rather than ending the group or not, terrorist groups may utilize higher levels of violence post-decapitation. Instead of simply being ineffective, leadership decapitation may in fact be counter-productive. Building on a principal-agent model as a theoretical lens, I explore the full effects of leadership decapitation. Without the leader’s more strategic perspective and assertion of operational control, group operative’s more violent preferences are often realized. Yet, without the organization and resources provided by a leader, these mechanistic groups are less efficient in their attacks post-decapitation. Consistent with this theory, examining 42,000 attacks from 133 terrorist groups over 46 years, leadership decapitation has the countervailing effect of a greater number of attacks post-decapitation, but lower levels of fatalities per attack.