Non-state actors shape our societies. While many pursue political change peacefully, some fuel instability and violence across entire regions. Yet, even under similar political conditions, organisations differ markedly in whether and when they resort to violence, whom they target and how far they escalate. What explains this striking variation?This book places resources and sponsors at the centre of the analysis. It argues that the type and origin of support available to political non-state organisations influence their tactical choices more decisively than existing research has recognised. Bringing together insights from studies on terrorism, civil war and social movements, the author develops an integrated, game-theoretic framework for understanding relations between organisations and the sponsors who sustain them. Central to this relationship are legitimacy costs arising when an organisation’s tactics diverge from its sponsors’ preferences. These costs vary according to the resources provided, their origins and the surrounding political context. The analysis also demonstrates that previous tactics are a powerful indicator of future behaviour. The proposed model of the Continuum of Escalation introduces a graded spectrum of tactics, offering the first systematic framework to connect resources, sponsors, target selection, and political context in explaining why some organisations remain peaceful while others move towards increasingly severe violence.
