Opinion polls have put opposition BJP party head Narendra Modi far ahead of the Gandhi-led Congress party.
Priyanka Gandhi Vadra, the youngest adult member of South Asia's most powerful political dynasty, weighed into India's increasingly bitter election campaign last week with a speech in the northern state of Uttar Pradesh.
Vadra (42) is the sister of Rahul Gandhi, the public face of the incumbent Congress party's fight to retain power for a third term, and the daughter of Sonia Gandhi, the Congress party's president.
"You have to decide whether you want politics where strength and power lies in the hands of the people or is vested in just one man," Vadra told a crowd in the impoverished rural seat of Rae Bareli.
A series of opinion polls have put the opposition Bharatiya Janata party (BJP), led by controversial Hindu nationalist Narendra Modi, far ahead of the Congress party.
A poll earlier this week indicated that the BJP may even achieve a majority, which would be a crushing defeat for the centre-left party led by the Gandhis.
Critics say Modi, who is chief minister of Gujarat, has authoritarian tendencies and is prejudiced along sectarian lines. Modi rejects both charges.
The Nehru-Gandhi dynasty has ruled India for most of the period since independence in 1947 but is increasingly unpopular even in its heartlands.
A series of corruption scandals, flagging economic growth and rising food prices have sapped its support after a decade in power.
A Congress minister said, on condition of anonymity, that Vadra, who is not standing for Parliament, was not seeking to upstage her elder brother but was simply "lending a hand".
"She has a formidable intellect and is working hard and loyally because her brother is travelling so much he cannot attend to every and all things at once," the minister said.
It has been reported that Congress is planning a more public role for Vadra, with suggestions that she might even stand as a Congress candidate against Modi (63) in the hugely significant seat of Varanasi, the northern holy city. The party eventually picked a "local" candidate.
In contrast to her older brother Rahul, Vadra is seen as charismatic, decisive and a good orator.
But she has said she will only campaign in the constituencies of her mother, Sonia, and her brother.
"The media is trying to make a big issue of it," said Congress party spokesperson Shakeel Ahmed. "She has said so many times her role is limited to the two constituencies. We should respect that decision."
Vadra is often compared to her grandmother, the immensely powerful and polarising prime minister Indira Gandhi, to whom she bears a striking resemblance.
Indira Gandhi was assassinated by her bodyguards in 1984 and her son, Rajiv, who was Gandhi Vadra's father, was killed in a suicide bombing in 1991.
Political analysts say Vadra is mediating between an "old guard" within the Congress party that is resisting reforms pushed by 43-year-old Rahul Gandhi, and a younger generation of parliamentarians and unelected officials who believe the party must change radically.
The BJP has dismissed Vadra's efforts, saying the Congress party's faith in one dynasty was its undoing.
"The family charisma has faded away ... the real solution to the problem is to make Congress a more structured party," the BJP's Arun Jaitley wrote in a blog post.
"The Congress party solution is [that] if one incumbent in the family fails, the alternative can only be another member of the family." – © Guardian News & Media 2014