After the Trinamool Congress in West Bengal, Maharashtra’s Shiv Sena (UBT) led by Uddhav Thackeray is facing a split, with a key NDA ally signalling a similar fate for the Samajwadi Party in Uttar Pradesh.Wednesday witnessed an unravelling of the Uddhav Sena with six out of nine Lok Sabha MPs meeting Speaker Om Birla to seek a merger with the Eknath Shinde faction of the party and shifting of the seats from the opposition to the treasury benches, backing the BJP-led NDA.Rebel Shiv Sena (UBT) MPs Sanjay Haribhau (Parbhani), Sanjay Patil (Mumbai North East), Bhausaheb Rajaram (Shirdi), Nagesh Patil (Hingoli), Sanjay Deshmukh (Yavatmal Washim) and Om Prakash Rajenimbalkar (Dharashiv), in a four-page letter to Birla, said they had no faith in the Uddhav Thackeray-led Shiv Sena (UBT) and feared it would merge with the Congress, which was a deviation from the ideology of Balasaheb Thackeray.The rebels said the Shiv Sena was not created to merge with the Congress. They will make a formal announcement regarding the merger with the Shinde faction on June 21.“We have taken seriously Sanjay Raut’s (Uddhav Sena leader) suggestion that the TMC should merge with the Congress. Tomorrow, the Shiv Sena (UBT) may do the same,” said one of the rebels, adding that they were merging with Shinde’s party and were not a separate bloc. The rebels also sent a letter to the EC saying that since they were a two-thirds of the Shiv Sena (UBT) strength in the Lok Sabha, the anti-defection law would not apply.Earlier today, Sena (UBT) leaders too shot a letter to Birla forewarning him against permitting any “unlawful defection”.Uddhav’s loyalist Lok Sabha MPs Arvind Sawant and Anil Desai, along with Raut, cited the Supreme Court’s 2023 judgment in defection matters to say that the political party is supreme and cannot be fragmented.“The Shiv Sena (UBT) continues to be recognised as a single political party represented in the House through its duly authorised leader and whip, and that no separate recognition, status, privilege or facility be accorded to any purported faction or breakaway group claiming to represent the party; no decision be taken on any such request, if received, without first affording the Shiv Sena (UBT) an opportunity to place its submissions before your office. The party further reserves all rights available to it in law, including the right to invoke the provisions of the Tenth Schedule and pursue such remedies as may be necessary in relation to any conduct inconsistent with the constitutional principles referred to above,” said the letter Sawant wrote to Birla.Late last night, Raut had alleged that the BJP was engineering a split in the Shiv Sena (UBT) by offering Rs 15-crore bribe each to the MPs in question.Today, Raut again attacked the rebels and used expletives against them.Meanwhile, the Shiv Sena (UBT) has called its parliamentary party meeting in Delhi on June 19 and has issued a three-line whip to all MPs to attend.The rebels, however, say since a two-thirds of the Sena (UBT) MPs have met Birla for a merger with the Shinde Sena, the whip issued by Uddhav’s faction does not hold.June 19 is also the Shiv Sena foundation day.This would be the second split in Uddhav’s party that Shinde would drive, the first being in 2022 when he defected from the parent party with a two-thirds of the MLAs, causing the fall of the Maha Vikas Aghadi and the installation of BJP leader Devendra Fadnavis-led Mahayuti government in Maharashtra.This saga of splits comes on the back of the government’s urge to touch a two-thirds majority mark in the Lok Sabha and pass the pending women’s reservation Bill, which has been linked to delimitation.The Constitution 131st Amendment Bill, 2026, was defeated in a recent special session by the joint opposition.Top government leaders have said they will pilot the Bill in the Lok Sabha as soon as they get a two-thirds number needed to pass a constitutional amendment.The TMC split, when formalised, will add 20 MPs to the NDA’s current 293-member kitty and the Sena (UBT) split, if it happens, will add another six. This would mean 319 MPs.The government, meanwhile, is in talks with the DMK, which has 22 MPs in the Lok Sabha, to support the Bill. Talks of a split in the SP, which has 37 MPs, have queered the pitch for the Congress-led INDIA bloc, which continues to unravel.In the current Lok Sabha, which has three vacancies and an effective strength of 540 MPs, the two-thirds mark is 360.