The Separation of Powers is a fundamental constitutional concept that divides the mechanism of governance into three distinct organs: the Legislature, the Executive, and the Judiciary. Its origin is often traced to the French political philosopher Montesquieu, who, in his 1748 work The Spirit of Laws, argued that liberty is best safeguarded by preventing the concentration of power in a single body. The problem it solves is the prevention of arbitrary, tyrannical, or irrational use of state power.
In India, the Constitution does not adopt the doctrine in its absolute, rigid sense, but rather a system of functional separation combined with checks and balances. The mechanism is established through various articles that delineate the functions of the three organs: the Legislature makes laws, the Executive implements them, and the Judiciary interprets them. For instance, Article 50 places an obligation on the State to separate the Judiciary from the Executive in public services. Conversely, there is a functional overlap, as seen in Article 123, which empowers the President (Executive) to promulgate ordinances (a legislative function) when Parliament is not in session.
The concept is intrinsically connected to the Basic Structure Doctrine. This connection was cemented in the landmark judgment of Indira Gandhi v. Raj Narain (1975), where the Supreme Court held that the separation of powers is a part of the Basic Structure of the Constitution. This means that Parliament, using its amending power under Article 368, cannot alter or destroy this fundamental feature. The doctrine was first established in Kesavananda Bharati v. State of Kerala (1973), where the Supreme Court ruled by a 7:6 majority that Parliament's power to amend the Constitution is not absolute and cannot be used to destroy its basic structure. While the core principle of functional separation has remained, the relationship has recently evolved, with the Judiciary asserting its role through judicial review to strike down laws that violate constitutional mandates.