Focusing on Iran in 2009 and Egypt in 2011, this paper examines the role of the coercive apparatus in responding to crises triggered by mass anti-regime protest. We argue that the divergent outcomes of the two crises – authoritarian resilience in Iran and regime breakdown in Egypt – can be traced to the regimes’ distinct origins. On the one hand, the Iranian Islamic regime’s founding in sustained, violent, and ideologically driven struggle (1978-1983) created a regime elite and coercive apparatus with the stomach and capacity for high intensity coercion necessary to defend the regime against mass-based threats. Revolution, counter-insurgency, and war during the regime’s early years led to the growth of an ideologically motivated and highly partisan security services. In Egypt, by contrast, the absence of origins in violent, revolutionary struggle led to the creation of a coercive apparatus with weaker, more situational cohesion. The regime’s overall coercive capacity was high, but in the absence of a revolutionary heritage, the willingness of the repressive apparatus to suppress large-scale, mass protest was more open to question than in Iran.