Decentralised Terrorism, Religion, and Social Identity

This paper offers a theory of decentralised, non-state-sponsored terrorism that is characteristic of contemporary reality, and that explains the rise of homegrown terrorism. We argue that the sense of social identity based on religion or shared history is a prime motivator of non-strategic terrorist activities, and we investigate its consequences and implications for defence against terrorism. Terrorist responses to perceived affronts to identity increase with altruism towards in-groups and with endogenous intensity of hate towards out-groups. We show that, while out-group spite is the more essential feature of identity pertinent to decentralised terrorism, the intensity of terrorist actions is magnified by in-group altruism because it plays an important role in overcoming the potential free-riding of terrorists. This makes individual terrorist activities possible without coordination. We use our formulation to provide an alternative explanation for why counterterrorism measures intended to deter and manage terrorism often fail, and frequently can have a backlash effect of actually increasing it. Our results point to the need for Western democracies to reformulate their foreign policies to take account of the role these policies play in instigating and managing contemporary terrorism.