Mrs Gandhi Vadra entered the fray earlier this month with a series of attacks on Mr Modi and other BJP leaders, which immediately boosted party morale and cast her as the "Gandhi with guts". Party insiders say she wants to lead Congress, but will not act until her brother renounces his own leadership ambitions.
One influential figure, who asked not to be named, contrasted her "natural communication skills" and ability to "connect with ordinary people" with her brother's "awkward, aloof" style.
Priyanka Vadra, daughter of Congress party president Sonia Gandhi, interacts with village women during an election campaign in her mother's constituency of Rae Bareli, India. Photo / AP
Tarun Gogoi, a senior Congress leader and Assam chief minister, last week called for Mrs Gandhi Vadra to play a "greater role in party affairs". At Shora Gangaganj in her mother's Rae Bareli constituency, poor women in bare feet waited in fierce midday heat last week to see Mrs Gandhi Vadra. She arrived with heavy security and a phalanx of Sports Utility Vehicles and was greeted with weak chants of "Long live Priyanka Gandhi."
Rae Bareli and Amethi have returned members of the Nehru-Gandhi dynasty or retainers as MPs in almost all general elections. Party insiders said they believe both Sonia Gandhi and her son will win their contests, but with reduced margins amid a growing revolt over the failure to improve basic local living conditions.
Mrs Gandhi Vadra focused instead on her own concerns at public criticism of her husband, the multi-millionaire businessman Robert Vadra, who is accused of exploiting poor farmers in Haryana and Rajasthan. He denies the allegations. "I feel sad when people in politics insult me and my husband but I have taken a lesson from Indira. The more people insult you, the stronger you come out. The more you insult me the more I will fight," she said.
Swapan Dasgupta, a conservative columnist, said Mrs Vadra Gandhi was a more natural leader than her brother, but the role still held dangers for her, due to her "imperious" manner and probable increased pressure over her and her husband's affairs.