Foreign Fighters as a Challenge for International Relations Theory

Although the existence of foreign fighters is nothing new in the inter- national arena, the phenomenon has not yet triggered a substantial reflection in International Relations (IR) theory. A relatively rare phenomenon before the 1980s, foreign fighters have so far received little attention under IR. This state of affairs began to change in the spring of 2014, when a jihadist armed group that incorporates an unprecedented number of foreign recruits—the Islamic State (IS)—proclaimed a ‘Caliphate’ spanning large portions of Syrian and Iraqi ter- ritory and captured global attention by widely circulating to the media all sorts of terror tactics and war crimes it systematically perpetrates. This chapter seeks first of all to bring foreign fighters into an IR analytical focus by identifying those trends that make them a discrete actor category distinct from insurgents and terror- ists. Second, it addresses some of the difficulties in grasping the question from an IR theory angle, beginning with transnational mobilisation and State sponsorship. Finally, it reflects on how foreign fighters are involved in State-making/un-making, and how this affects movements in the tectonics of the international system