A bitter family feud risks hurting the re-election chances of the Samajwadi or Socialist Party, which has been a dominant political force in Uttar Pradesh, India's most populous state.
The state goes to the polls early next year and the internal trouble has raised doubts about whether the party can counter an aggressive election campaign by Prime Minister Narendra Modi's Bharatiya Janata Party (BJP). The Samajwadi also faces another major rival, Bahujan Samaj Party leader Mayawati, popularly known as Behenji or sister, who is seeking to return to power after five years in opposition.
With more than 200 million people, about three times the population of Britain, Uttar Pradesh is a huge political prize. It has 80 MPs in the Upper House of Parliament, the largest representation of any state.
At the heart of the row are Uttar Pradesh Chief Minister Akhilesh Yadav, 43; his uncle Shivpal Singh Yadav, 61; and his father Mulayam Singh Yadav, the 76-year-old founder of the party and a one-time wrestler who became a politician.
Disputes remain over who will decide the party's election strategy even as the party says the family is working through its differences.
Mr Sudhir Panwar, a member of the state's Planning Commission, said: "The older generation (led by Mulayam) wants a strong hold on the party, while Akhilesh Yadav has said that since the mandate is on his government, he has to decide the election strategy."
Still, the warring factions united on Thursday to flag off the party's election bus on a campaign that will see the Chief Minister - who last month sacked his uncle from the Cabinet - tour the state.
Said Mr Akhilesh Yadav: "Due to some conspiracies, we were a bit rattled, but in the days to come, we will be able to form a government again."
He is the party's modern face and wants to focus on development, in contrast to the old guard who at one point were even opposed to using English in schools and technology, such as using laptops.
Dr Aftab Alam, a political science professor at Aligarh Muslim University, said: "They are trying to show a united front but, in fact, what is happening inside is a deep gap between Shivpal and Akhilesh.
"It is visible at the ground level."
The politics of the regional parties in Uttar Pradesh has traditionally been rooted exclusively in caste.
The Samajwadi Party counts Yadavs, a powerful land-owning community, among its core supporters but also has appeal among Muslims.
For now, it seems that Ms Mayawati, whose core supporters are the Dalits and also sections of the Muslim population, could have a slight edge over her regional rival. The BJP, considered a party of upper castes, has also been reaching out to other castes, including the Dalits.
Amid the infighting, Mr Mulayam Yadav has reached out to other regional parties and the opposition Congress party, fuelling talk of a coalition against the BJP.
"It is a very fluid situation. There is a lot of uncertainty about these elections," said Dr Alam. "The Muslims... don't know who to vote for. The majority will vote for whoever gives the best alternative to the BJP. That will be the rule of thumb."