NEW DELHI - The Congress has suffered a political setback following the resignation of Mr Jyotiraditya Scindia and around 22 legislators in Madhya Pradesh state, deepening an existential crisis for a party that is struggling for political relevance in modern Indian politics.

Mr Scindia, 49, an articulate leader, on Wednesday (March 11) joined Prime Minister Narendra Modi's Bharatiya Janata Party (BJP), with the legislators loyal to him also joining the BJP, potentially leading to the collapse of the Congress-led Madhya Pradesh government.

The BJP now has an opportunity to form the government in a Hindi heartland state which has been seen as important to the party. The BJP has always drawn its strength from the Hindi heartland and used it to extend its reach in the vast country.

Once considered close to Congress leader Rahul Gandhi, Mr Scindia was said to be disenchanted for some time over not being chosen as Madhya Pradesh chief minister. The post went to Mr Kamal Nath, a senior Congress leader.

Mr Scindia belongs to the erstwhile royal family of Gwalior, whose members have served on both sides of the political divide. His father, Mr Madhavrao Scindia, was a prominent Congress leader but his aunts, including former Rajasthan chief minister Vasundhara Raje and Madhya Pradesh legislator Yashodhara Raje, are in the BJP.

"While my aim and purpose remain the same as it has always been from the very beginning, to serve the people of my state and country, I believe I am unable to do this any more with this party," he said in his resignation letter to Congress president Sonia Gandhi which was posted on Twitter.

After officially joining the BJP on Wednesday, he told a press conference: "Congress is no longer what it used to be; it is living in denial."

Soon after, the BJP announced that it was nominating Mr Scindia to the Upper House of Parliament.

The resignation of Mr Scindia, considered one of the bright sparks of the Congress party, comes amid ferment within what was once the grand old party of Indian politics which led the fight for independence from British colonial rule.

Congress has suffered back to back losses in the general election in 2014 and 2019 and seen its political influence wane across the country.

Mr Gandhi quit as Congress president shortly after the election results last year and his mother, Sonia, who is known to be in poor health, took over the role.

The party that once dominated Indian politics appears to have ceded the opposition space to smaller regional parties in different states. It faced another humiliating loss in recent elections in the capital city Delhi, which was a Congress bastion, when it managed to garner only four per cent of the vote. The incumbent Aam Aadmi Party romped back to power ahead of the BJP.

The electoral losses have seen many senior Congress leaders speak out.

Mr Shashi Tharoor, a former foreign minister and UN undersecretary-general, said the time has come to change the perception in the public that the party is adrift with voters driven towards other political alternatives.

Another Congress leader, Mr Jairam Ramesh, took aim at the old guard leaders, suggesting that they were unwilling to cede power to the next generation.

Still, Congress has put on a brave face following the resignation of Mr Scindia, who is not known to be a leader of the masses. Mr Kamal Nath expressed confidence that his government would survive the upheaval. Congress leader Digvijay Singh also maintained that 13 of the 22 legislators were also not keen on joining the BJP.

Others in the Congress accused Mr Scindia, who has been critical of the BJP in the past, of political opportunism.

Many analysts saw the resignation as a boost for the BJP.

"It will help reinvigorate the BJP, especially if they manage to form the government in Madhya Pradesh, after facing a defeat in Delhi," said Dr N. Bhaskara Rao, chairman of the Centre for Media Studies.

"Scindia is not a mass leader. But it will have a demoralising impact on the Congress and its cadres, junior and senior. There is something dramatically wrong within the Congress and it is just not able to come out of its decline."