The split in the Mamata Banerjee-led TMC and the rebel faction’s decision to ‘merge’ with lesser known Nationalist Citizens Party has once again exposed the limits of the Tenth Schedule of the Constitution – popularly known as anti-defection law.Related news: Constitutional expert questions plan of TMC rebel MPs to seek ‘real TMC’ status from Speaker“Two-thirds MPs of TMC have given a letter to the Speaker for a separate seating arrangement. We will merge with the Nationalist Citizens Party and support the NDA,” rebel MP Kakoli Ghosh Dastidar told reporters after meeting Lok Sabha Speaker Om Birla.Claiming that two-thirds of the TMC Lok Sabha members had submitted a letter seeking recognition as a separate group, she requested Birla to make a separate seating arrangement in the House for rebel TMC MPs.Added to the Constitution through the 52nd Amendment in 1985, The Tenth Schedule’s validity was upheld by the Supreme Court in Kihoto Hollohan vs Zachillhu and Others in 1991.It envisages two circumstances when a lawmaker can be disqualified—if he/she voluntarily gives up membership of a party and when he/she votes/abstains from voting contrary to party directive.Originally, the Tenth Schedule recognised a ‘split’ in a legislature party if at least one-third members formed a new group or joined another party. But, after the 91st Amendment which came into force in 2004, the law recognises a ‘merger’ that requires at least two-third members of a legislature party to join another one or form a new one without falling foul of the anti-defection law.In Subhash Desai versus Principal Secretary, Governor of Maharashtra i.e. the Shiv Sena split case (2023), the Supreme Court distinguished between a “legislative party” and a “political party,” saying they cannot be conflated. Now, the joining of another party is not a valid defence in disqualification proceedings under the Tenth Schedule unless the original political party itself merges with another party.A five-Judge Constitution Bench led by the then CJI DY Chandrachud also ruled that the power to appoint a whip and the leader of the party in the House rested solely with the political party, not the legislative party. The rebel faction of a political party cannot unilaterally replace the party’s whip and that the Speaker must recognise only the whip and leader authorised by the parent political party, it said.The anti-defection law as interpreted by the Supreme Court in the Shiv Sena split case, requires a formal organisational merger of the original political party and at least two-thirds of the elected lawmakers must agree to the merger in order to avoid disqualification.When Dastidar announced that the rebel TMC faction along with two-thirds of its MPs will merge with the Nationalist Citizens Party, she was only trying to meet the pre-conditions for a constitutionally valid goodby to the TMC without facing the wrath of the anti-defection law.This is just the beginning of a long-drawn legal battle expected to unfold in the Supreme Court after the Speaker takes a decision on the rebel TMC MPs’ status in the House and the Election Commission gives its verdict on claims and counterclaims for the TMC’s election symbol.