The numbers behind Tamil Nadu’s political earthquake

E-PaperSubscribeSubscribeEnjoy unlimited accessSubscribe Now! Get features like The most shocking election result in this cycle has come from Tamil Nadu, the largest state in south India and the fifth largest in terms of number of Lok Sabha MPs among states. The political debutant Tamilaga Vettri Kazhagam (TVK) formed by the film star Vijay has finished first in the state with 107seatsleaving behind the Dravida Munnetra Kazhagam (DMK) and All India Anna Dravida Munnetra Kazhagam (AIADMK) led alliances. To be sure, the TVK has still fallen short of the halfway mark in the assembly of 234 and government formation will take some post-poll understanding. How does one explain this result? Here are four key data points which matter. Both the DMK and the AIADMK have recorded among their worst ever contested vote shares in Tamil Nadu. (DMK website)Tamil Nadu politics has gone back to being triangular after 50 yearsNot only does this show in the fact that a party or alliance has failed to get a majority of its own in the state, it also shows in the more esoteric statistical measure of degree of political fragmentation. The median effective number of parties (ENOP) in Tamil Nadu in the 2026 elections is 3.23. This number has crossed three for the first time in the state after the 1977 elections. ENOP is the reciprocal of sum of squares of vote share of each candidate in a constancy. This means that if three candidates polled exactly equal vote shares ENOP will be 3. If the three parties had a vote share of 70%, 20% and 10%, ENOP will be 1.85. Unless one of the three parties sink, Tamil Nadu politics is entering historically uncharted territory after this election. Both the DMK and AIADMK face a moment of reckoning now The TVK is the second debutant political force after the Aam Aadmi Party (AAP) to have made an impressive debut in a state election in India is the recent past. What makes the TVK’s stellar debut in these elections even more special is the fact that it has inflicted huge pain on both the incumbent as well as the main opposition party in Tamil Nadu. AAP’s entry into politics was different because it primarily hurt the Congress rather than the BJP in Delhi, where it first made political impact. Both the DMK and the AIADMK have recorded among their worst ever contested vote shares in Tamil Nadu. This makes the TVK’s success a damning indictment of the entire political establishment in Tamil Nadu. Of the 159 constituencies won by the DMK+ in 2021, only 54 stayed with the alliance in 2026. TVK+ captured 77 of them, while ADMK+ took 28. The AIADMK’s 2021 map was also breached. Of the 75 seats won by AIADMK+ last time, TVK+ won 30, ADMK+ retained 25 and DMK+ won 20. This can also be seen in the breaching of party-wise strongholds in the state. There were 57 assembly constituencies that were won by the same party in all three elections between 2011 and 2021. Of these, AIADMK held 38, DMK 16 and Congress three. In 2026, AIADMK retained only 14 of its 38 strongholds, while DMK retained 10 of its 16. TVK won 16 AIADMK strongholds and three DMK strongholds, showing that the party’s breakthrough was not confined to swing seats. The symbolic centre of this shift was Kolathur, where chief minister M K Stalin lost to TVK’s V S Babu. Kolathur had been Stalin’s seat since 2011 and was widely seen as a DMK bastion. The AIADMK’s damage was different. Edappadi K Palaniswami retained Edappadi, but TVK broke through in the western region, the AIADMK’s most important zone. See Chart 3: https://datawrapper.dwcdn.net/teeAH/1/ The DMK alliance is better off than AIADMK because of its allies DMK and AIADMK alliances will have 74 and 53 MLAs in the new assembly. The difference between DMK and AIADMK’s own tallies is much lower: 58 and 46 respectively. The reason, the DMK alliance has a much larger tally than AIADMK is a better performance by its allies. This shows clearly in the strike rate of DMK and AIADMK and their allies in the state. The worst strike rate among allies of the DMK and the AIADMK is that of the BJP, just 3%. The BJP contested the highest number of ACs among the AIADMK’s allies. It will not be wrong to say that the poor performance of the BJP carries a larger message for the AIADMK and other parties in the state. See Chart 4: https://public.flourish.studio/visualisation/28819272/ Roshan Kishore is the Data and Political Economy Editor at Hindustan Times. His weekly column for HT Premium Terms of Trade appears every Friday.