The Basic Structure Doctrine was propounded by the Supreme Court of India in the landmark Kesavananda Bharati vs State of Kerala case (1973). The Court held that Parliament's power to amend the Constitution under Article 368 is not unlimited and cannot be used to alter, amend, or repeal the 'basic structure' or essential features of the Constitution. The Preamble, embodying core ideals like justice, liberty, equality, fraternity, sovereignty, socialist, secular, and democratic republic, is often considered to contain some elements of the basic structure, though the basic structure itself is a judicial concept that has evolved over time through various judgments.