The Berubari reference
In re: The Berubari Union and Exchange of Enclaves
Held. On a reference by the President under Article 143, the Court advised that ceding Indian territory to a foreign State (here under the Nehru–Noon agreement with Pakistan) could not be done by an ordinary law under Article 3; it needed an amendment of the Constitution under Article 368.
Why it matters. The Constitution (Ninth Amendment) Act, 1960 followed. The reference is also the case usually cited for the view, later revised in Kesavananda, that the Preamble is not part of the Constitution.
Later Answered by Kesavananda Bharati (1973) · The amending power and the basic structure