Revolutions may be defined as periods in which the rate of change of power positions of factions, social groups, or armed bodies changes rapidly and unpredictably. Revolutions then come to an end to the degree that political uncertainty is reduced by building enough bargains into a political structure that can maintain those bargains. The paper summarizes what we know about the structures that can produce such decreases in uncertainty: conservative authoritarianism, independence, occupation government, totalitarianism, democracy, and caudillismo. The paper describes these governmental types by how they increase certainty of power distributions in the short and medium run and so bring revolutions to an end.
