To the crowd standing amid the blackened wrecks of their cinder-block houses — which burned to the ground last August after the water supply was mysteriously cut off, residents said — she put it more bluntly.
“The only person the governor fears is Putin,” she said of the Russian president, Vladimir V. Putin. The governor, she added, “does not care what you think about him because you do not vote for him.”
Elections in Russia, especially presidential elections, have a somewhat remote connection to voting. Since first becoming president in 2000, Mr. Putin has instituted a system of “managed democracy,” which basically means the Kremlin controls the entire process.
Mr. Putin, 65, who is expected to declare his candidacy for a fourth term in the next few weeks, is considered a shoo-in, given how the system seems designed to thwart challengers. To qualify, independent candidates have to collect signatures and passport details from 300,000 people in 43 regions, for example. That is just one hurdle, and many candidates end up being disqualified.
Roughly 25 candidates have declared their intention to run thus far, but Ms. Sobchak stands apart in that she has national name recognition on the same scale as Mr. Putin’s. There is a family connection as well. Her father, as mayor of St. Petersburg, brought Mr. Putin into politics by making him his deputy.
Ms. Sobchak was fired from various lucrative jobs on state television after becoming one face of the political protests surrounding the last dubious presidential election, in 2012. She then capitalized on her name recognition to become a social media star, attracting more than 5.3 million followers on Instagram and over 1.6 million on Twitter, using both accounts to shill for designers, stores, car companies, exercise studios and other lifestyle brands.
Ms. Sobchak, 36, married for five years with one infant son, makes no apologies for continuing that line of work. “Yes, I love good clothes, good shoes, but I earned it,” she said.
At her main public forum in Rostov, she cited the Decembrists, a group of early-19th-century aristocrats exiled for trying to challenge the absolute power of the czar, as one of her inspirations.
“Many of them soon left their palaces for Siberia,” she said. “I achieved what I did by myself, and at some point realized that I should make sure that life is better for everybody, not just for me.”
Skeptics abound, and many question whether Ms. Sobchak is opposing the current czar or doing his bidding. Every recent presidential election has featured a high-profile liberal candidate handpicked by the Kremlin. Hence some accuse her of being a spoiler to undermine the campaign of Aleksei Navalny, an anticorruption campaigner who has spent more than a year organizing a presidential bid.
Ms. Sobchak denies that, and suggests that voters want an alternative to the confrontations and street demonstrations promoted by Mr. Navalny. “When you go with very radical slogans, you only make people more angry,” she said, with unpredictable consequences. “Revolutions in Russia are even worse than bad czars.”
By making “Against Thieves” part of her campaign slogan, she has adopted part of Mr. Navalny’s platform. But there were obvious differences. Ms. Sobchak flew in on business class and arrived at the venue in a chauffeured black Mercedes an hour late, after stopping to get her hair done.
Her crowds seemed sparser and less energetic than Mr. Navalny’s, though she has siphoned off some Navalny supporters. “Navalny will not be allowed to register, and I want to take part in the vote,” said Andrei Sotskov, a 53-year-old boxing coach. “I have heard her called a spoiler, but there is nothing to prove this theory.”
Other critics on the left condemn her for focusing on the “system” rather than more bluntly on Mr. Putin and legitimizing what they consider a sham by running.
“What is the goal of running against a candidate with 100 percent chance of success?” wrote Karina Orlova, a Russian journalist, in a blog post.
To her credit, Ms. Sobchak has broken new ground by openly discussing political topics previously regarded as taboo: the veiled costs of annexing Crimea, the negative influence of the Russian Orthodox Church on policy issues, political prisoners, hidden pollution, corrupt judges, the government monopoly over television and the rationale behind the wars in Syria and Ukraine.
In a move that suggests the Kremlin wants at least the semblance of a debate, she and a few other opposition figures have recently been allowed to appear on Kremlin-controlled television channels. Ms. Sobchak has been on twice since October, including an appearance on a late-night talk show on which she was the only guest. That appearance descended into a shouting match with the famous host over who was the worse government lackey.
Some people discount her candidacy because she is a woman. In a recent poll by the Levada Center, an independent pollster, 53 percent of respondents said they did not think a woman could run the country, and 32 percent said no current female politicians were qualified. The poll was based on 1,600 respondents last September.
In Rostov, Yulia Kirichenko, a 28-year-old working in internet marketing, said she had showed up partly to endorse the idea of a female politician.
“It is very unusual to have a strong woman in Russia who goes into politics, so I think we need to support her in this,” she said.
Some suspect that Ms. Sobchak’s candidacy is mostly about building her brand, particularly since she often concedes that she cannot win. She said she was just being honest, and planned to stay in politics for the long haul. Unless Mr. Putin fiddles with term limits again, he will be out in 2024 and there is no designated successor.
“Of course I want to be president, I want to win, but I also want to be sincere,” she said. “In a system created by Putin, it is only possible for Putin to win. I am realistic about who will become the president.”