Undisputedly, the core recognition of the 101st Amendment is associated with the introduction of the Goods and Services Tax ('GST') which resulted in subsuming of a number of indirect taxes into a unified GST, levied by the Union Government and the State Governments. Adoption of GST undoubtedly revolutionized the concept of One Nation – One Tax – One Aspiration and seeks to play a pivotal role in catapulting the economic growth of the nation to its fullest potential in the years to come. The earlier system of multiple indirect taxes at different levels of the value chain had started to plague the entire system and clearly GST was a panacea to the same. The GST system has certainly resulted in a much simpler tax eco system as is in vogue currently. In summation this phase of Fiscal Unification was indeed historical. GST is levied on the supply of goods and services or both. It is a single unified indirect, multi-stage, destination-based tax levied on every value addition.

The new system has targeted ensuring a more robust, efficient and a consistent supply chain across the nation consequentially realizing the goal of overall price rationalization. The cumulative effect of its adoption is the percolation of the ensuing benefits to the last mile consumer.

It is in-fact the tectonic shift in "cooperative federalism" which was at the heart of the 101st amendment. The amendment was a compact yet comprehensive Act of 20 sections primarily resulting in insertion, repealing and amending of Articles in the Constitution of India marking a new era of simultaneous but harmonious exercise of power by the Union and the States on a subject.

Since its origin, the Constitution contained a three-fold distribution of legislative power. Under Article 246, the subjects of legislation enumerated in the Union List of the Seventh Schedule were assigned to Parliament, those in the State List were assigned exclusively to the States and those in the Concurrent List were assigned both to Parliament and the States with precedence to Parliament under the provisions of Article 254. This position stood completely altered qua GST, with the 101st amendment which introduced article 246A.

Article 246A(1) provided for a unique source of power exercisable concurrently by the Parliament and the Legislature of a State. It expressly overrides Article 246 and 254 and accordingly represents the exclusive source of power to legislate on GST. Within the scheme of 246A, a further exclusivity of power is conferred on the Parliament to make law with respect to GST where the supply of goods, or of services, or both takes place in the course of inter-State trade or commerce. It is for the first time that an article seeks to embody a constitutional principle of simultaneous levy as distinct from the principle of concurrence. It is in this light that there has been a paradigm shift in creating a unique repository of source of power for the simultaneous legislation on a defined subject by both the Union as well as the State.

Consequential changes in the definitions contained in article 366 as also the changes made in the respective entries of List I and II were also made which in terms aligned the spirit of these substantive amendments in the respective articles.

The next vital article which took birth as a consequence of the 101st amendment was Article 269A dealing with the framework for the Levy and Collection of GST in the course of inter-state supplies. While, as per the scheme of Article 246A and 269A, power to levy and collect GST on such inter-state sales is with the Government of India but the same is subject to the spirit of due apportionment of the collected tax between the Union and the States, in accordance with the law enacted by the Parliament in this regard on the recommendation of the GST Council. While the first part of article 269A(1) read with article 246A (2) highlights the exclusivity enjoyed by the Union Government on the subject of 'levy' and 'collection' of the GST on the supplies in the course of inter-state trade, the latter part of the article expressly caveats such an exercise by providing for the manner in which the fruits of the said collection are to be split between the two stakeholders. Article 279A is also a unique provision. It provides for the creation of GST Council as a Constitutional Body and envisages it as a virtual torch bearer for GST issues. The nature of the constitution of GST Council is again reflective of the joint and cooperative spirit of GST framework which seems to be implicitly embedded across all the insertions brought in by the 101st amendment.

In summary, this spirit of cooperative Federalism being the soul of the GST framework needs constant nurturing and preservation. It is the inherent spirit of just sharing that will hold the key to the concept of co-operative Federalism in the coming times. In the event of any disruptions in this line of harmony, the scope and true intent of the source of power and its inherent limitations under these constitutional provisions will get tested. While all the stakeholders need to undoubtedly rejoice in the successful implementation of the historical changes ushered in the form of GST framework in the past few years but must equally tread carefully for ensuring continued success in dealing with challenges that are likely to arise in future. There are very few legislations which affect an individual so fundamentally as this Amendment has and it is therefore imperative that each stakeholder plays a constructive part in ensuring its continued success.