After four decades of working with the Congress, former Meghalaya Chief Minister DD Lapang quit the party on Thursday with a letter to Rahul Gandhi, pointing at senior leaders being sidelined in the party.
Mr Lapang, 84, lost in the Meghalaya assembly election only once in 1993, and had been representing Nongpoh constituency, 51 km from Shillong, since 1972. The Congress removed him as its state chief last year.
In his resignation letter to Congress president Rahul Gandhi, the former chief minister said the party appears to consider seniors as no longer useful for it.
"In my opinion, it means that their (senior and elderly party leaders) service and contribution are no longer useful to the party. Since the spirit and enthusiasm to work for the people are still burning inside me, this restriction frustrated and compelled me to be no longer comfortable to be in the party," Mr Lapang said.
"With my present age and health condition, I have decided to continue serving the people of the country, my state and its people in the same manner wherever I am," he said. "Therefore, reluctantly and with my heavy heart, I would discontinue my dedication towards the Congress party and I tender my resignation with immediate effect."
The impact of his resignation from the Congress in the general elections next year is difficult to predict, sources say, as he was no longer the state party chief.
Conrad Sangma, the 40-year-old chief of the National People's Party (NPP), went on to form the new government earlier this year after stitching an alliance following the assembly election. The Congress got 21 seats and Mr Sangma's party 19 seats.
With the backing of 33 legislators, Mr Sangma became successful in dethroning the Congress's two-time chief minister Mukul Sangma.