a change of government by force is a
Regime change Regime change can be precipitated by revolution or a coup d'état. The Russian Revolution, the 1962 Burmese coup and the 1990 collapse of communism in Eastern Europe (→ #Dissolution of the Eastern Bloc) are consummate examples.
Separation of powers The separation of powers is a model for the governance of a state. Under this model, a state's government is divided into branches, each with separate and independent powers and areas of responsibility so that the powers of one branch are not in conflict with the powers associated with the other branches. The typical division is into three branches: a legislature, an executive, and a judiciary, which is the trias politica model. It can be contrasted with the fusion of powers in some parliamentary systems where the executive and legislative branches overlap.