The Dravidian major is said to have been unnerved by the DMDK's choice to align with the rival front, at a time when the PMK is grappling with internal divisions, a party vertically split between father Ramadoss and son Anbumani. These failures have made it increasingly difficult for the alliance to consolidate votes in the northern districts.

Until the last minute, AIADMK leaders expected the DMDK to join the NDA, in vain. The DMDK is believed to have a vote share of around two per cent, with a notable presence in northern districts, where the party is said to command between 5,000 and 10,000 votes in several constituencies.

The PMK, meanwhile, remains divided. While Anbumani Ramadoss is part of the NDA, the party's founder, S Ramadoss, has so far refused to join the alliance. This has created uncertainty within the alliance, with concerns that it may dent its prospects, particularly in Vanniyar strongholds.

Sources said these developments have delayed the formation of NDA committees to negotiate seat-sharing arrangements.

Senior journalist Tharasu Shyam told DT Next that the AIADMK didn't anticipate DMDK’s move. He said PMK founder Ramadoss appeared inclined to contest independently under the present circumstances and could field candidates against those backed by Anbumani Ramadoss. Such a scenario, he added, could lead to a split in votes that might otherwise have gone to the NDA.

Responding to the development, AIADMK youth wing secretary Paramasivam said DMDK's choice would not alter the electoral outcome. He said the AIADMK believed in the people’s mandate and asserted that there would be no significant deviation of votes region-wise, adding that the party and its present alliance have the strength to win the elections this time.