Counterterrorism Killings and Provisional IRA Bombings, 1970–1998

Counterterrorism strategies involving the killing of terrorists are a prominently used but controversial practice. Proponents argue that such strategies are useful tools for reducing terrorist activity, while critics question their effectiveness. This article provides empirical insight into this strategy by conducting a series of negative binomial regression and Tobit estimations of the impact of killing Provisional Irish Republican Army (PIRA) terrorists as well as members of the Catholic community on counts of PIRA bombings and targeting activity in Northern Ireland for the period 1970–1998. We consider the impact of discriminate and indiscriminate killings (where only PIRA militants are killed versus those in which both militants and civilians are also killed) on subsequent PIRA improvised explosive device (IED) attacks. Our findings illustrate that while total and discriminate counterterrorism killings have little to no effect on PIRA IED attacks, indiscriminate counterterrorism killings increased PIRA bombings overall and prompted the Provisional IRA to specifically target civilians in IED events. We conclude by discussing the scholarly and policy implications of these findings.