The principle that the legislative, executive and judicial functions of government should be vested in separate organs so that no single organ accumulates unchecked power. Associated with the French thinker Montesquieu.
- India follows a functional, not rigid, separation: the three organs have distinct core functions but overlap, with a system of checks and balances.
- The legislature makes laws, the executive enforces them, and the judiciary interprets and adjudicates; the parliamentary system fuses the executive with the legislature, unlike the strict American model.
- Articles touching the principle include Article 50 (a Directive Principle urging separation of the judiciary from the executive), Article 121 and 211 (bar on discussing judges' conduct in legislatures) and Article 122 and 212 (courts not to question legislative proceedings).
- Held to be part of the concept basic structure in Kesavananda Bharati (1973) and reaffirmed in Indira Nehru Gandhi v. Raj Narain (1975) and the I.R. Coelho case (2007).
- Functional overlaps include the President's ordinance power, delegated legislation, and the judiciary's rule-making and contempt powers.
It is a core feature of the Constitution and a recurring basic-structure item; the distinction between the rigid American model and India's checks-and-balances model is commonly tested.
India does not follow a strict or absolute separation; the organs deliberately overlap, restrained by checks and balances rather than watertight compartments.
Montesquieu's separation of legislative, executive and judicial power, applied functionally in India with checks and balances; part of the basic structure.