Until 1971, it was widely thought that since the Indian Constitution does not mention the provisions which are amendable under Art. 368, any part of the Constitution was amendable provided it fulfilled the requirements laid down in this article. But in the legendary Keshvanand Bharati Vs. State of Kerala Case, the Supreme Court ruled (overruling its own judgment in the Golak Nath Case) that though not expressly mentioned, there are certain provisions in the Constitution which make up its “basic structure”, and therefore, are not changeable at all.
This decision is widely known as the “basic features theory”. The basic features as spelt out by the Supreme Court are
1. Sovereignty and territorial integrity of India
2. The federal system
3. Judicial Review
4. Parliamentary system of government
Strangely enough, the fundamental rights have not been included in this theory. Consequently, theoretically at least, the Parliament can change or abolish any or all of the Fundamental Rights. Very recently, secularism has been included in this list by the Supreme Court in the BJP Ruled States Vs. Union of India Case.
In the subsequent tug-of-war for supremacy between the Legislature and the Judiciary, the above judicial attempt by the Supreme Court to assert its authority was nullified by the 42nd Amendment Act. The Act aimed at excluding all kinds of judicial review by the Court. Reacting to this, the Supreme Court ruled in the Minerva Mills Case that judicial review is one of the basic features and that it cannot be taken away by any law. Summing up this complicated scenario, the net position is like this:
1. Any part of the Constitution is amendable according to Art. 368 provided it does not change any of the “basic features” mentioned above.
2. No Constituent Assembly has to be convened nor any referendum is required (like in Switzerland) to amend the Constitution.