Killing Two Birds with One Stone? Examining the Diffusion Effect of Militant Leadership Decapitation

This note analyzes the effectiveness of leadership targeting in deterring militant operations. It broadens how we think about their deterrence effects by including nontargeted groups. I argue that leadership decapitation of one group signals to other would-be aggressors a state's capability and determination to deploy such actions against them. Nontargeted groups are thus forced to recalculate the cost-benefit balance of conducting further attacks, which leads to indirect deterrence. Using the Global Terrorism Database from 1970 to 2008 and Price's (2012) leadership decapitation data, targeted capturing is found to deter operations by nontargeted groups, and this effect is magnified when those militants form an alliance. While targeted killing is frequently executed through drone strikes, incurring lower costs and risk for the state, the findings indicate that killing a leader does not reduce militant operations. Policymakers should recognize the unintended effect deriving from one leadership decapitation and transform it into an intended outcome to maximize their expected payoffs.