Separation of Powers

The division of government among legislative, executive, and judicial branches

Overview

Articulated by Montesquieu and embedded in the American Constitution with checks and balances, separation of powers aims to prevent tyranny by making ambition counter ambition. Presidential systems divide strictly, while parliamentary systems fuse legislature and executive while keeping courts independent. Its modern fights range from war powers to agency structure and emergency rule. The principle is now the common grammar of constitutional design worldwide, whatever the local accent. The vocabulary entered every postwar constitution, whatever the local balance of strength among the branches.