Goods and services tax authority: Parliament exclusively governs inter state supplies, States may otherwise legislate under constitutional provision. The amendment inserts a special constitutional provision authorising Parliament and, subject to limitation, State Legislatures to make laws with respect to goods and services tax while giving Parliament exclusive power where supply occurs in the course of inter State trade or commerce, and providing that, for GST matters referenced to another constitutional article, the provision takes effect from the date recommended by the GST Council.