The separation of powers between Legislature, Executive and the Judiciary constitutes basic structure, has been found in Kesavananda Bharati's case by the majority. Later, it was reiterated in Indira Gandhi's case. A large number of judgments have reiterated that the separation of powers is one of the basic features of the Constitution.
In fact, it was settled centuries ago that for preservation of liberty and prevention of tyranny it is absolutely essential to vest separate powers in three different organs. In Federalist 47, 48, and 51 James Madison details how a separation of powers preserves liberty and prevents tyranny. In Federalist 47, Madison discusses Montesquieu's treatment of the separation of powers in the Spirit of Laws (Boox XI, Ch. 6). There Montesquieu writes, "When the legislative and executive powers are united in the same person, or in the same body of magistrates, there can be no liberty. . . Again, there is no liberty, if the judicial power be not separated from the legislative and executive." Madison points out that Montesquieu did not feel that different branches could not have overlapping functions, but rather that the power of one department of government should not be entirely in the hands of another department of government.
Alexander Hamilton in Federalist 78 remarks on the importance of the independence of the judiciary to preserve the separation of powers and the rights of the people:
"The complete independence of the courts of justice is peculiarly essential in a limited Constitution. By a limited Constitution, I understand one which contains certain specified exceptions to the legislative authority; such, for instance, that it shall pass no bills of attainder, no ex post facto laws, and the like. Limitations of this kind can be preserved in practice in no other way than through the medium of courts of justice, whose duty it must be to declare all acts contrary to the manifest tenor of the Constitution void. Without this, all the reservations of particular rights or privileges would amount to nothing." (434)
Montesquieu finds tyranny pervades when there is no separation of powers:
"There would be an end of everything, were the same man or same body, whether of the nobles or of the people, to exercise those three powers, that of enacting laws, that of executing the public resolutions, and of trying the causes of individuals."
The Supreme Court has long held that the separation of powers is part of the basic structure of the Constitution. Even before the basic structure doctrine became part of Constitutional law, the importance of the separation of powers on our system of governance was recognized by this Court in Special Reference No.1 of 1964 [(1965) 1 SCR 413].