In the Kesavananda Bharati case3 (1973), the Supreme Court overruled its judgement in the Golak Nath case (1967). It upheld the validity of the 24th Amendment Act (1971) and stated that Parliament is empowered to abridge or take away any of the Fundamental Rights. At the same time, it laid down a new doctrine of the ‘basic structure’ (or ‘basic features’) of the Constitution. It ruled that the constituent power of Parliament under Article 368 does not enable it to alter the ‘basic structure’ of the Constitution. This means that the Parliament cannot abridge or take away a Fundamental Right that forms a part of the ‘basic structure’ of the Constitution.

The doctrine of basic structure of the constitution was reaffirmed and applied by the Supreme Court in the Indira Nehru Gandhi case3a (1975). In this case, the Supreme Court invalidated a provision of the 39th Amendment Act (1975) which kept the election disputes involving the Prime Minister and the Speaker of Lok Sabha outside the jurisdiction of all courts. The court said that this provision was beyond the amending power of Parliament as it affected the basic structure of the constitution.

Source: Indian Polity by Laxmikanth