[Answered] Tracing the evolution of basic structure doctrine in India highlights its salient features.

The basic structure doctrine is an Indian judicial principle, which means that the Constitution of India has certain basic features that cannot be altered or destroyed through amendments by the parliament. The doctrine forms the basis of power of the Supreme Court to review and strike down constitutional amendments and acts enacted by the Parliament which conflict with or seek to alter the basic structure of the Constitution.

Evolution of basic structure doctrine in India: 

1. Initial stance: The Supreme Court’s initial position on constitutional amendments was that any part of the Constitution was amendable and that the Parliament might, by passing a Constitution Amendment Act in compliance with the requirements of article 368, amend any provision of the Constitution, including the Fundamental Rights and article 368.
2. Shankari Prasad case: In the Shankari Prasad case (1951), the constitutional validity of the First Amendment Act (1951), which curtailed the right to property, was challenged. The Supreme Court ruled that the power of the Parliament to amend the Constitution under Article 368 also includes the power to amend Fundamental Rights.
3. Sajjan Singh v. State of Rajasthan: The Constitution has “basic features” was first theorized in 1964, by Justice J.R. Mudholkar in the case of Sajjan Singh v. State of Rajasthan. He questioned whether the ambit of Article 368 included the power to alter a basic feature or rewrite a part of the Constitution.
4. Golaknath vs. State of Punjab: In Golaknath vs. State of Punjab, Supreme Court held that Fundamental Rights of the Constitution are given a transcendental position and are beyond the reach of Parliament. It also declared any amendment that takes away or abridges a Fundamental Right conferred by Part III as unconstitutional.
5. Kesavananda Bharati case: The concept of basic structure was finally introduced by Supreme Court in the Kesavananda Bharati case 1973. In this landmark ruling, the Court adjudicated that while Parliament has wide powers, it did not have the power to destroy or emasculate the basic elements or fundamental features of the constitution.
6. Indira Gandhi case: In Indira Gandhi vs. Raj Narain, 1975, the Supreme Court reaffirmed its concept of basic structure.
7. Minerva Mills Case: Under Minerva Mills Case (1980), the Supreme Court ruled that Judicial Review is included in Basic features of the Constitution.
8. Waman Rao Case: In Waman Rao Case (1981), it was held that the doctrine will be applied to Constitutional Amendments after the Kesavananda Bharati Case Judgement.
9. Kihoto hollohan case: In Kihoto hollohan vs. Zachillhu, 1992, ‘Free and fair elections’ was added to the basic features.
10. Indira Sawhney case: Indira Sawhney vs. Union of India, 1992, ‘Rule of law, was added to the basic features.
11. R Bommai case: In S.R Bommai vs Union of India, 1994, Federal structure, unity and integrity of India, secularism, socialism, social justice and judicial review were reiterated as basic features

Salient features of basic structure doctrine:

1. Restricted amending powers: The concept of Basic Structure has not been mentioned in the Constitution, neither there was a restriction on the amending powers of Parliament. Basic structure doctrine restricted the amending powers of Indian Parliament.
2. Supremacy of the Constitution: It reiterated that the constitution is supreme and has certain basic components that can’t be touched.
3. Unity and sovereignty of India: According to basic structure India’s sovereignty and unity is inherent and can’t be removed. It restricted parliament’s power to alter federal provisions solely.
4. Democratic and republican form of government: India is a democracy and a republic and hence is driven by its people.
5. Secular character of the Constitution: India is a secular country as mentioned in preamble and this secular provision is a basic doctrine.

The basic structure doctrine has been used by the Supreme Court in subsequent judgments to preserve the sanctity and basic character of the Constitution. The doctrine has evolved through SC judgments and is still expanding. It forces constitutional amendments to conform to certain standards or values that maintain the sanctity and spirit of the Constitution.