With six Lok Sabha MPs of the Shiv Sena (UBT) joining the Shiv Sena on Monday, another anti-BJP regional party has fallen to a palace coup. The Sena (UBT) defections follow the implosion of the Trinamool Congress after its loss in West Bengal. What does one make of these developments? This question can be answered from three perspectives.Sena’s dynastic patriarch committed political harakiri by stitching together an ideologically incoherent alliance with the Congress and NCP, and subsequently saw the majority of his party walk away to join hands with the BJP. (Raju Shinde/HT Photo)The first is of immediate parliamentary interest. The NDA is closing in on the two-thirds majority threshold in Parliament with these defections. To be sure, it is still 41 and nine seats short of the required numbers in the Lok Sabha and Rajya Sabha. However, the momentum has decisively shifted from a couple of months ago, when it had to withdraw the clubbed legislations for women’s reservation and delimitation. Will it try to push this electorally consequential bill once again in the next session and change the state of play for 2029 contest? We will know in less than a month.The second is the dynamic within the NDA. The BJP-Shiv Sena relationship in Maharashtra is the proverbial political potboiler. The BJP, initially a junior partner, outperformed the Sena and made it insecure post-2014. Sena’s dynastic patriarch committed political harakiri by stitching together an ideologically incoherent alliance with the Congress and NCP, and subsequently saw the majority of his party walk away to join hands with the BJP. Eknath Shinde, who brought the Sena back to the BJP, had his wings clipped after losing the chief minister’s chair in 2024. Monday’s defections — Shiv Sena now has the most Lok Sabha MPs in the NDA from Maharashtra — will renew his bargaining power vis-à-vis the BJP, especially within Maharashtra, even as it makes the BJP stronger nationally.The third is the Opposition’s growing predicament. Its biggest trump card before the 2024 Lok Sabha election was forging the INDIA bloc to ace the all-in-unity tactic against the BJP. State elections since then have seen INDIA bloc partners lose badly, disintegrate, and quibble with each other instead of reimagining or reinventing their challenge to the BJP. The irony is difficult to miss. The BJP has gained at the cost of not just the opposition but also its allies. The Congress continues to do badly itself and is also seeing its allies atrophy.What is driving this schism? The shortest answer is that the Indian polity is in a winner takes all phase right now.