We develop a model of regime dynamics that embeds the principal transition scenarios examined by the literature. Political systems are a priori unrestricted and dynamics emerge through the combination and interaction of transition events over time. The model attributes a key role to beliefs held by political outsiders about the vulnerability of regimes, governing the likelihood and outcome of transitions. In equilibrium, transition likelihoods are declining in a regime's maturity,generating episodes of political stability alternating with rapid successions of revolts, counter revolts, and reforms. The stationary distribution of regimes is bimodal. The model dynamics match the data remarkably well