When Dr. B.R. Ambedkar introduced the draft Constitution in the Constituent Assembly in 1948, he underlined the deliberate attempt of its makers to describe India as a Union of States and not a federation. “The federation is a Union because it is indestructible,” Dr. Ambedkar said.
He said that the Constitution was empowered to change its form and shape into unitary or federal as needed: “…the draft Constitution can be both unitary as well as federal according to the requirements of time and circumstances. In normal times, it is framed to work as a federal system. But in times of war, it is so designed as to make it work as though it was a unitary system,” he reasoned.
The final version provided demarcation of powers between the Centre and States in terms of legislative, administrative and financial functions, while the Seventh Schedule further divided the legislative functions into Union, State and Concurrent lists.