The principle of separation of powers states that the executive, legislative, and judiciary powers of government should be divided into different branches and not concentrated in one. The intent is to prevent the concentration of power and provide for checks and balances. The separation of powers, often imprecisely and metonymically used interchangeably with the trias politica principle, 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 legislature are unified.