Russian journalist and Putin challenger defends herself against claims she is a Kremlin plant Ksenia Sobchak sat down with ABC News to discuss her campaign.

 -- In the early 1990s, when Russian presidential candidate Ksenia Sobchak was 11 years old, she said she would open the front door for Vladimir Putin when he came to her home. Putin was there to see her late father, Anatoly Sobchak, who served as the mayor of Saint Petersburg during the troubled years after Soviet Union's fall. The elder Sobchak became Putin's boss after appointing him deputy mayor; later, he would become Putin’s mentor, setting the ex-KGB agent on his path to the Kremlin.

Now, Ksenia Sobchak, 35, has formally launched a presidential campaign to challenge Putin in the election next spring. Running under a slogan of "Against Everyone," Sobchak has described her bid as a protest vote for Russia's marginalized opposition to rally around in an election whose outcome will all but certainly be in Putin's favor.

A top journalist at one of Russia's only liberal television stations, Sobchak has long been a fixture in Russian media. But for many years, she was better known as a reality TV star, hosting the sex-fueled Russian version of "Big Brother" and her own show that followed her party-girl lifestyle and earned her the nickname "Russia's Paris Hilton" in the Western press. Her family ties to Putin were such that she has had to deny rumors she was his goddaughter.

Her presidential campaign, however, has caused a rift in the anti-Putin opposition, sparking allegations that she is a Kremlin Trojan Horse, a stage-managed candidate meant to defang a sharper challenge from another leader, anti-corruption campaigner Aleksey Navalny.

Critics have alleged her run must have been approved, if not proposed, by Putin's government. Those suspicions were fueled in the weeks leading up to her announcement by leaks to newspapers alleging the Kremlin was looking for a woman to run against Putin and considered her "an ideal candidate." Since making her announcement, she has been barraged by criticism that she is -- willingly or not -- a prop in the Kremlin’s latest political show.

Ksenia Sobchak met with ABC News in a makeup room backstage after appearing on a popular talk show on a state TV channel Wednesday. She had been on to speak about her campaign, a scenario that would be unthinkable to others in Russia's opposition, who have long been barred from state television.

For months, state media avoided even mentioning Navalny's name, and some viewers of Sobchak's talk show appearance noted that the host, Andrey Malakhov, seemed to do just that, skipping over any mention of Navalny.

Sobchak explained that her access to state TV is a sign that the Kremlin "underestimates" her. She denied the Kremlin encouraged her to run, saying she decided to do so after talking with friends, particularly some businessmen she won't name, who committed to fund her.

A week into her campaign, she told ABC News that she is using the Kremlin's approval to her advantage.

"In the eyes of the authorities, in Putin's eyes -- and this is even what I am counting on -- maybe this situation even seems useful to them and that they can use me," Ksenia Sobchak said. "But I believe we must use this situation ourselves."

In a political system heavily controlled by the Kremlin, where even the second-most popular candidate, communist Zennady Zyuganov, polls at under 2 percent of the vote compared to Putin's 53 percent, this does not mean winning.

"Let's not make out as though I will be the winner. I won't be," Ksenia Sobchak said. "Putin will run and he will win."

The idea, she said, is to instead use her candidacy to show how Russians are unhappy with Putin's rule and to muster opposition forces for future battles. She first has to get on the ballot though, by collecting at least 100,000 signatures, or 300,000 if she runs without a party backing.

Like much of the anti-Putin opposition, her campaign’s aesthetic recalls that of an American tech start-up. The makeup room is full of Sobchak’s young aides, dressed in sneakers and hipster T-shirts. She portrays her bid as a selfless, kamikaze run to ensure the anti-Putin opposition is represented this spring and to push Russia toward a more democratic path.

"Ask me if this is the best way? No. It's what we have, for now," she said. "It's not very much."

But, she added, "I am ready to bring myself as a sacrifice to this situation."

But Sobchak’s liberal critics feel that by running, she is not sacrificing her own future but rather Navalny's.

Navalny, an anti-corruption activist who made his name exposing officials’ alleged ill-gotten wealth, has become Russia's most dynamic opposition leader. For months, he has been breathing life into the country's smothered political scene, occasionally bringing thousands onto the streets in the largest anti-government protests in years. Using social media and grassroots organizing, he has built a movement of 170,000 volunteers in 80 cities, mobilized around his attacks on official corruption and demands for real political competition.

Russian authorities have responded by disrupting his rallies and repeatedly arresting him. Navalny has been jailed seven times since December for calling unauthorized demonstrations. He was finishing his latest 20-day stint in jail when Sobchak announced she was entering the presidential race.

Navalny is formally barred from running by a fraud conviction he said is politically motivated, but is running what he calls a “presidential campaign” in any case, demanding to be allowed onto the ballot. Whether the Kremlin will ultimately allow him to run for president was set to become a defining issue in the election.

Ksenia Sobchak's announcement, however, changes that. Navalny's supporters have accused Sobchak of being a spoiler for him, meant to dampen the inevitable controversy if the Kremlin blocks him and to siphon off some of the popular dissatisfaction he is channeling.

But Sobchak insists she has no interest in blocking Navalny and has said she will withdraw her candidacy if he is allowed on the ballot. Navalny "deserves" to be the opposition’s lead candidate, she told ABC News. But, she said, the opposition needs to be ready in case he is not allowed to run.

"If they unfairly deprive him of that opportunity, we have to be in a state to accept that as a fact and all the same act, and not sit at home," she said.

After making a career around her personal brand, she now argues she can be a blank figurehead just to get the opposition through the door. "What difference does it make if it's me?" she said.

Many in the close-knit opposition have scoffed at that, while others have parodied Sobchak. Zoya Tsvetova, a well-known political analyst and critic of Putin, asked in a blog post Open Russia whether Ksenia Sobchak is "ashamed" to run, given that she must know she is playing by the Kremlin’s rules.

And on Monday, another well-known female journalist and singer-songwriter, Ekaterina Gordon, announced she would also run for the presidency, in an acerbic challenge to Sobchak. “I am not a representative of glamor, I wasn’t born with a silver spoon in my mouth,” Gordon said in video launching her campaign.

Even the wife of her campaign manager, a liberal journalist, published a post on Facebook saying she was shocked her husband had agreed to work with Ksenia Sobchak. One of Sobchak’s chief advisors quit on Tuesday, according to the newspaper RBC, taking part of his team with him, saying the campaign was in chaos and ill-conceived. Most other opposition leaders though, including the exiled oligarch Mikhail Khodorkovsky, have so far largely rallied around her run or avoided directly criticizing it.

Navalny, speaking on his weekly Youtube show, said he prefers to say as little as possible about her bid, arguing that a public quarrel among the opposition is exactly what the Kremlin wants.

Nonetheless, on Tuesday he told British newspaper The Independent that if he is blocked from running, he will not tell his supporters to vote for Ksenia Sobchak.

"If I'm not allowed to run, the elections would not be elections. Of course we'd have to boycott them," he told The Independent.

Ksenia Sobchak argues that a boycott would be more damaging and that Navalny's politics of street protest also don't appeal to many of those who are otherwise opposed to Putin.

"People can't go into the street endlessly,” she said. “My friends get asked why aren't they going to the next protest? They answer, 'Because we're tired of being thousands. I'm ready to become the 100,000th person at a rally, but I don't want to be the 10,000th. Because it's pointless.'"

Even if far from ideal, the legal protest vote is the alternative, she said. But her critics warn that they have seen this before.

In 2012, billionaire oligarch Mikhail Prokhorov ran on a similarly loose liberal platform, again allegedly at the Kremlin’s encouragement. He won 8 percent of the vote.

Maksim Katz, an opposition commentator and activist, has said the seriousness of Ksenia Sobchak’s bid should be judged on how tough she is on Putin.

In 2012, Prokhorov avoided criticizing Putin personally. In her interview with ABC News, Sobchak was also mild in her critique of the current administration.

"I believe that he possesses his own perception about what really is good for our country," she said of Putin. "I don't believe that he is doing what he does exclusively from some kind of greed. I don’t believe that a person in power for so many years can be as concerned as before with just how he can make it so he can steal more money."

That contrasts starkly with Navalny, who refers to Putin as a "thief" and has pledged to put him and his circle on trial.

Some also question just how tough Ksenia Sobchak can be on Putin, given her family's history. In the 1990s, when Anatoly Sobchak was under investigation for corruption, he was hospitalized following a heart attack. When warrants were issued for his arrest, Putin arranged for him to travel to Paris. Anatoly Sobchak, who died in 2000, later campaigned for Putin.

Ksenia Sobchak has said she believes Putin saved her father's life, but that doesn’t blind her to his current political shortcomings.

"Even if he was an ideal president," which he is far from, she said, "he is all the same still a person who has been in power a very long time. And that shouldn't be."

She offers up a family comparison.

"I don't know. I have my mother. I love her very much, but on many issues, we will never find a common language, because she simply doesn't understand many things. Vladimir Putin is a person from a different generation," Sobchak said.

She said she won’t call for Putin to leave power, saying it’s not realistic. The opposition’s role now is to try to influence the Kremlin, she said, and to prepare for what comes next when Putin leaves power.

Sobchak said she believes Putin will not run for another term in 2024, but will pick a successor. That is what the opposition should be preparing for now, she said.

"Our most important elections aren't now. The most important elections will be in six years, when he won't run," she said of Putin. "I am also sure of that."

Her current campaign has signalled she is preparing for that possibility -- the domain name for one of her campaign sites is sobchak2024.ru.