In Tamil Nadu, elections are not decided by party arithmetic alone. Across its regions, dominant caste blocs — vanniyars in the north, gounders in the west, thevars in the south, and dalit and nadar communities in key pockets — continue to shape alliances, candidate selection and, often, the final result.Vanniyars are concentrated in northern districts like Viluppuram, Dharmapuri, Krishnagiri, Salem, Cuddalore and Vellore. The influential OBC community rose to political prominence after Vanniyar Sangam, led by S Ramadoss, spearheaded violent protests that preceded the introduction of 20% quota for Most Backward Classes in 1989 by the M Karunanidhi govt.The community has since then largely backed PMK, founded by Ramadoss and now under the disputed control of his son, Anbumani Ramadoss. Sizeable sections of vanniyars have also aligned with DMK and ADMK. This time, Anbumani’s PMK faction, an NDA member, is contesting 18 seats, while Ramadoss senior has fielded candidates in 35 seats, mostly in the northern belt.

Shortly before the 2021 assembly polls, ADMK govt introduced a 10.5% internal quota for vanniyars, but Supreme Court struck it down. The incoming DMK govt took a cautious line, maintaining that only the Centre has the legal authority to conduct a caste census.The DMK govt has three senior ministers from the community. “Both DMK and ADMK allot more seats to vanniyars, which shows the community’s significance,” says Vanniyar Federation founder-president C N Ramamurthy. DMK also received a boost last week when Guru Viruthambigai, daughter of the late PMK leader Guru, met CM MK Stalin to offer support.If vanniyars are central to the north, gounders continue to hold sway in western Tamil Nadu, particularly in Coimbatore, Erode and Salem districts. Large sections continue to support leaders from the community such as ADMK general secretary Edappadi K Palaniswami and former ministers SP Velumani and P Thangamani. KA Sengottaiyan, another community veteran, has crossed over to Vijay’s TVK.In the 2021 assembly election, the western belt was the only region that stayed with the ADMK, which won 29 of 48 seats there. This time, Stalin has assigned the region to former minister V Senthilbalaji. “DMK candidates will win in several constituencies in the western region and we will form the next govt,” Senthilbalaji told TOI . In southern Tamil Nadu, thevar influence remains strong in districts such as Ramanathapuram, Sivaganga, Virudhunagar, Theni and Madurai. The mukkulathor grouping — comprising the Kallar, Maravar and Agamudaiyar communities — has long been regarded as a key support base of the ADMK, especially during the tenures of MGR and Jayalalithaa.But that base has shown signs of strain. Sections of the community were upset over perceived slights by Palaniswami, who expelled three prominent leaders from their fold from the party: AMMK chief TTV Dhinakaran, former chief minister O Panneerselvam, and Jayalalithaa aide V K Sasikala. In 2021, the ADMK won just 16 of 58 seats in the south, where the DMK and Congress won 33 and eight seats respectively.Panneerselvam has since joined the DMK. Sasikala has launched the All India Puratchi Thalaivar Makkal Munnetra Kazhagam and fielded 77 candidates with the stated objective of defeating ADMK nominees. Her campaign is centred on the theme of “Palaniswami the betrayer”.Dalits remain another key electoral force, with their population ranging from 15% to 34% in many districts, except Kanyakumari, where their numbers are relatively low. SC such as paraiyar, pallar and arunthathiyar continue to carry significant political weight.DMK ally VCK, led by Thol Thirumavalavan, remains a prominent voice among dalit voters, particularly within the paraiyar community in the north.Among pallar leaders, S Krishnasamy of Puthiya Tamilagam is contesting independently in 60 seats after alliance talks with ADMK failed. In the NDA camp, John Pandian, who heads a dalit outfit, has been fielded from Rajapalayam on BJP’s lotus symbol. Vijay’s TVK and Seeman’s NTK have also made some inroads into dalit vote banks.In several southern pockets, outcomes also depend on nadars, the economically influential community in Tirunelveli, Tenkasi, Thoothukudi, Virudhunagar and Kanyakumari. Historically, the community aligned with Congress, largely because of former CM K Kamaraj, a nadar, who played a key role in enabling reservation for backward classes through the First Amendment to the Constitution.Following Jayalalithaa’s death, ADMK lost much of its nadar support because of the leadership’s perceived affinity towards gounders and vanniyars. The DMK has since occupied some of that space, with Kanimozhi Karunanidhi, the party’s MP from Thoothukudi, focusing considerable attention on the region. BJP leaders Tamilisai Soundararajan and Pon Radhakrishnan also count among the community’s prominent faces.