The Supreme Court adjourned for two weeks a petition filed by Shiv Sena UBT MP Arvind Ganpat Sawant challenging the merger of rebel MPs with the Eknath Shinde-led Shiv Sena faction. The Speaker's non-appearance caused the adjournment. The case tests whether the merger of legislators meets the Tenth Schedule threshold, which requires at least two-thirds of a party's legislative strength to merge validly without inviting disqualification.

The Tenth Schedule of the Constitution, inserted by the 52nd Constitutional Amendment Act 1985, governs anti-defection. It disqualifies a legislator who voluntarily gives up party membership or votes against party direction. Crucially, it originally recognised a 'merger' exception: if at least two-thirds of the legislature party merged with another party, members were not disqualified. The 91st Constitutional Amendment Act 2003 abolished the split exception (one-third) but retained the merger exception (two-thirds).

The Speaker is the adjudicating authority under the Tenth Schedule for state assemblies; for Parliament, it is the Speaker of the Lok Sabha or the Chairman of Rajya Sabha. In Kihoto Hollohan v. Zachillhu (1992), the Supreme Court upheld the Tenth Schedule's validity but ruled that the Speaker's disqualification decisions are subject to judicial review. In Nabam Rebia v. Deputy Speaker (2016), the Court held that a Speaker facing a removal motion cannot decide disqualification petitions.

The 2022 Shiv Sena split culminated in Subhash Desai v. Principal Secretary (2023), where a five-judge Constitution Bench ruled that the Speaker cannot recognise a faction as the 'real party' and that the Election Commission is empowered to decide the original party symbol dispute. The current UBT petition now extends this constitutional battle to the parliamentary level, testing whether MPs who joined the Shinde faction satisfy the two-thirds merger threshold under Para 4 of the Tenth Schedule.