The Basic Structure Doctrine in India refers to the principle that certain fundamental features of the Constitution are immutable and cannot be altered even through constitutional amendments. Established by the Supreme Court in the landmark case of Kesavananda Bharati v. State of Kerala (1973), this doctrine safeguards essential elements such as the supremacy of the Constitution, secularism, federalism, and the separation of powers.

The doctrine ensures that the Parliament cannot amend the Constitution in a manner that alters its core identity and fundamental principles. It acts as a bulwark against arbitrary changes that could undermine the constitutional framework and the rights of citizens. The judiciary has consistently upheld this doctrine by striking down amendments that seek to tamper with its core features. For instance, in cases like Indira Gandhi v. Raj Narain (1975) and Minerva Mills v. Union of India (1980), the Supreme Court reaffirmed its authority to review amendments and declared those infringing upon basic structure as unconstitutional.
By upholding the Basic Structure Doctrine, the judiciary reinforces the supremacy of the Constitution and ensures that any amendments are in harmony with its foundational values, thereby preserving the integrity and stability of India’s constitutional framework.