How sharing of power between the Union Government and the State governments is basic to the structure of the Constitution.?

Sharing of power between the Union Government and the State governments is basic to the structure of the Constitution. It is not easy to make changes to this power sharing arrangement. The Parliament cannot on its own change this arrangement. Any change to it has to be first passed by both the Houses of Parliament with at least two-thirds majority. Then it has to be ratified by the legislatures of at least half of the total States.