MGR is expelled from the DMK — and builds a bigger party in six days

M. G. Ramachandran (MGR) was one of the DMK's biggest draws — a hugely popular film star who had been the party's treasurer since the mid-1960s — but he had been drifting from party leader M. Karunanidhi's inner circle since 1971, when Karunanidhi turned down his push for a cabinet role, citing the conflict between movie stardom and government office. MGR responded by building his own network of fan clubs across the state, which the party leadership saw as a rival power base.

Matters came to a head when MGR publicly accused the DMK government of corruption. On 11 October 1972, 26 of the 32 members of the DMK's executive council signed a memorandum calling for disciplinary action, and MGR was suspended from the party's primary membership.

He didn't stay out of politics for long: on 17 October 1972, just six days later, MGR founded the Anna Dravida Munnetra Kazhagam (later All India Anna Dravida Munnetra Kazhagam, AIADMK), taking a significant chunk of the DMK's cadre and fan base with him. The new party won power in its first election it contested as the lead partner, in 1977, and MGR was Tamil Nadu's Chief Minister from 1977 until his death in 1987 — the start of a DMK–AIADMK rivalry that has defined Tamil Nadu politics ever since.