Violent non-state actor ecology and the effects on counterinsurgency and statebuilding

Abstract Violent non-state actors (VNSAs) typically adopt one of three organizational forms: market, network, or hierarchy. These forms affect the duration of conflicts, as well as their intensity, chances of success, and vulnerability to counterinsurgency. What drives this adoption and with what effects for counterinsurgency and statebuilding? To answer, I first use a computational model of organizational ecology to show that VNSAs adopt organizational structures in response to population dynamics and environmental pressures. Built on a simple model of cooperation (the iterated prisoner’s dilemma), the model shows that rebel organizations form as networks when populations are small and rebels believe the risks of defection are low, but shift to more costly, hierarchical organizational forms to protect themselves from defection as these risks increase or as the benefits of fighting increase. I find that those most vulnerable to exploitation are more likely to join hierarchies at relatively lower levels of risk than more reconcilable insurgents. Having established drivers of VNSA ecology absent intervention, I next demonstrate the importance of accounting for organizational alternatives in counterinsurgency and statebuilding strategies.