The control of the Trinamool Congress (TMC) slipping from Mamata Banerjee in Bengal, six of nine MPs of Uddhav Thackeray's Shiv Sena (UBT) going to Eknath Shinde’s Sena in Maharashtra, seven AAP MPs switching to the BJP in Delhi and Punjab — defections are unfolding in almost all regions of India at once. And a case most likely to decide who avoids the anti-defection law is from the beach state of Goa, pending in the country's top court.Supreme Court of India has in a 2023 case observed that MPs alone are not the whole party, but that was not part of a direct verdict on mergers as such. (HT File Photo)All of these upheavals in Opposition parties, taking the defectors to PM Narendra Modi’s BJP-led NDA side, come with the same question of constitutional law. That is, what are the exceptions to the anti-defection law in the Tenth Schedule of the Constitution?In April, seven of AAP's ten Rajya Sabha MPs, led by Raghav Chadha, switched to the BJP.Poll results in May gave the BJP its first government in West Bengal, and now 20 of the defeated TMC’s 28 Lok Sabha MPs have declared a merger with a little-known Nationalist Citizens Party of India (NCPI) as per consultations with the BJP.Around the same time, six of Shiv Sena (UBT)'s nine Lok Sabha MPs have moved to defect to the Shinde-led Shiv Sena.In each case, the fate of the rebels turns on questions that courts have, at best, only partly resolved.The merger exceptionIndia's anti-defection law was introduced in 1985. It disqualifies any legislator who voluntarily gives up party membership or defies a party whip (direction). It originally allowed two escapes: a “split” and a “merger”. The split exception was deleted in 2003 after being routinely abused.Only merger survives, under Paragraph 4 of the Tenth Schedule. This para has two parts.(Sub) Paragraph 4(1) protects a legislator where “the original political party… merges with another political party”.(Sub) Paragraph 4(2) then says, “For the purposes of sub-paragraph (1) of this paragraph, the merger of the original political party of a member of a House shall be deemed to have taken place if, and only if, not less than two-thirds of the members of the legislature party concerned have agreed to such merger.”The battle is largely over whether these two parts are to be read together or separately.If read together, the parent political party must first merge with another party, and two-thirds of the legislature party (meaning MLAs or MPs) merely has to confirm it.If read separately, the two-thirds vote of MPs is itself enough to create a merger, with no decision by the parent party needed.What the Goa case heldThe Bombay High Court, in a Goa defection case, went with reading them separately. In 2019, 10 of 15 Congress MLAs in Goa crossed to the BJP. That meant two-thirds of the Congress legislature party. The Congress and BJP never merged as political parties, as we know. The Goa assembly speaker accepted the mere movement of MLAs as a valid merger. And when the matter reached the HC, it upheld the speaker’s decision.Constitutional experts say the HC read (Sub) Paragraph 4(2) in isolation. “That reading is not correct,” former Lok Sabha secretary-general PDT Achary told HT.com. Constitutional commentator Sourya Gopal Mukherji has written that the second part of Paragraph 4 in fact begins with the words “for the purposes of sub-paragraph (1)”. That would mean both conditions have to be fulfilled — the political party has to merge, and two-third of its MLAs or MPs (legislature party) has to give its nod too. An appeal against that HC decision in the Goa matter — ‘Girish Chodankar vs The Speaker, Goa Legislative Assembly’ — is now with the SC.SC has addressed issue: Is it enough?The SC has spoken on the subject in another case, ‘Subhash Desai vs Principal Secretary, Governor of Maharashtra’ in 2023, in a Constitution Bench ruling on the original Shiv Sena split between Uddhav Thackeray and Eknath Shinde.That case did not involve a merger claim as such, because the Shinde faction claimed to be the real Shiv Sena itself. (It later got the name and symbol from the Election Commission too.)But the SC judgment, authored by then CJI DY Chandrachud, spoke of a wider principle, that legislators alone are not the whole party. “To read the term 'political party' as 'legislature party' would be contrary to the plain language of the Tenth Schedule,” it said. It also warned: “This is not the system of governance that is envisaged by the Constitution. In fact, the Tenth Schedule guards against precisely this outcome.”What remains to be settledThe catch is that the ‘Subhash Desai 2023’ case about Shiv Sena formally only covered appointment of whips and leaders, not the question of merger. The SC's observations on Paragraph 4 and merger are part of its reasoning in the judgment, but not a direct verdict on that issue.Yet, former LS secretary-general Achary is categorical that no further clarification is needed. He said the language of the law is clear on its own: Step 1 is that the leadership of a political party decides to merge with another party; and Step 2 is that its MLAs and MPs (the legislature party) have to agree for the merger to be okayed. “MPs or MLAs alone cannot merge with another party. That is the constitutional provision,” he told HT.com. He further said the presiding officer of the relevant House — say, the Lok Sabha speaker in case of the TMC or Sena-UBT rebellions — has to follow this “settled principle”. A beleaguered TMC has also put exactly this argument on record in a letter to LS speaker Om Birla. Party general secretary Abhishek Banerjee cited the ‘Subhash Desai 2023’ judgment to argue that the TMC is a “single, indivisible political party” and that its legislative party in the Lok Sabha exists only as “an emanation of” the parent organisation.Similar questions about merger and switches have come up over the past two months at the assembly level in Bengal and Tamil Nadu.Keeping focus on Parliament though, the shadow of rebellion has fallen allegedly also on the Samajwadi Party, another major constituent of the Congress-led INDIA bloc. UP deputy CM Keshav Prasad Maurya of the BJP has claimed that “around 25-26 MPs of Samajwadi Party are ready to break away”. Party chief Akhilesh Yadav has rejected the claim. The SP has 37 Lok Sabha MPs, meaning 25 would meet the two-thirds threshold.But can they act on their own? The question goes back to the pending Goa matter in the SC. The impacted parties in the latest defections have also expressed hope for a resolution through the constitutional courts.Why the numbers matterThe question of two-thirds is not limited to defecting MPs. The BJP-led NDA needs two-thirds majority in both Lok Sabha and Rajya Sabha to amend the Constitution. The NDA hit a wall on that front recently.On April 17, the Modi government's Constitution (131st Amendment) Bill — which sought to expand the Lok Sabha and carry out delimitation or (redrawing) of constituencies, as a prerequisite to women's 33% reservation — was defeated as NDA does not have two-thirds majority. It got 298 votes against a required 352. Every MP who now switches to the NDA narrows that gap.