Separation of powers is the division of a state's government into branches, each with separate, independent powers and responsibilities, so that the powers of one branch are not in conflict with others. The typical division into three branches of government, sometimes called the trias politica model, includes a legislature, an executive, and a judiciary. It can be contrasted with the fusion of powers in monarchies, but also parliamentary and semi-presidential systems where there can be overlap in membership and functions between different branches, especially the executive and legislative.

In political science, power is the social production of an effect that determines the capacities, actions, beliefs, or conduct of actors. Power does not exclusively refer to the threat or use of force (coercion) by one actor against another, but may also be exerted through diffuse means.