India, May 12 -- When Tamil Nadu chief minister C Joseph Vijay faces a trust vote for his TVK-plus-five-allies government on Wednesday, the outcome will matter far beyond whether his rule survives beyond three days. The vote has become the stage for another consequential drama, on whether the AIADMK, once the dominant force in Tamil Nadu politics, holds together or fractures just weeks after its worst election performance in decades.

Vijay's Tamilaga Vettri Kazhagam (TVK) won 108 seats in the April 23 assembly elections, results of which came on May 4 - a remarkable debut for a party barely two years old. But 108 falls short of the 118 needed for a majority in the 234-seat assembly. Vijay formed the government with support from Congress,...