Fusion of powers

Fusion of powers is a feature of some parliamentary forms of government where different branches of government are intermingled or fused, typically the executive and legislative branches. It is contrasted with the separation of powers found in presidential, semi-presidential and dualistic parliamentary forms of government, where the membership of the legislative and executive powers cannot overlap. Fusion of powers exists in many, if not a majority of, parliamentary democracies, and does so by design. However, in all modern democratic polities the judiciary does not possess legislative or executive powers.

The system first arose as a result of political evolution in the United Kingdom over many centuries, as the powers of the monarch became constrained by Parliament. The term fusion of powers itself is believed to have been coined by the British constitutional expert Walter Bagehot.