Bengaluru, April 16 -- Social engineering isn't something most people would associate with election strategies in a state like Tamil Nadu, yet, with a week remaining for the elections (on April 23), it is this that may decide whether the ruling Dravida Munnetra Kazhagam (head of the Secular Progressive Alliance) staves off the challenge from the All India Anna Dravida Munnetra Kazhagam (head of the National Democratic Alliance in the state). Data point to a consistent pattern in Tamil Nadu: a significant number of constituencies decided by narrow margins, often under 5,000 votes, or roughly 2-3% of votes polled. That means even smaller caste-based parties, with limited but concentrated vote bases, can decisively tilt outcomes. "The 2021 res...