Taking on Vladimir Putin can be a dangerous business.
Many political opponents are barred from running against him. Others find themselves in jail or worse.
Russian opposition politician Boris Nadezhdin has not only criticised Mr Putin's war in Ukraine and called for it to end, but also announced plans to run against the president in next month's election.
In doing so he's had to confront very real fears about his safety. But he has now come to the conclusion Mr Putin and the Kremlin also fear him, and could try and stop him from standing.
Mr Nadezhdin has told the ABC the country's leadership "understand that I can rise very, very high" in polling because of his anti-war stance.
"I am absolutely sure that dozens of millions of people in Russia want to change the president, and they want Russia to be a peaceful and free country."
The 60-year-old liberal has the potential to embarrass the Kremlin during the campaign at a time when it wants to portray Mr Putin as one of Russia's great wartime leaders.
Mr Nadezhdin says if he becomes president, he would end the war in Ukraine, release political prisoners such as Alexei Navalny and Ilya Yashin, and seek a global agreement between Russia and Western nations.
"We should stop the rockets flying in Belgorod [in Russia], and we should not have rockets flying to Kharkiv or Kyiv," he says.
"Immediately [we need to] stop the fire. Because the main problem is that people kill each other, and people should not destroy cities. This is problem number one.
"The second problem, a much harder problem, is to make a new agreement, a global agreement between the Russian Federation and the Western community."
But first, he must get on the ballot paper.
Last week, Mr Nadezhdin delivered what he said were more than 100,000 signatures to Russia's Central Election Commission, something required before a candidate can run for president.
During the past month, thousands of his supporters have queued in the snow across many regions in Russia to provide their signatures.
But in a sign Mr Nadezhdin may be barred from running, officials have already challenged some of those signatories, saying they found "dead souls" on their lists.
Nikolai Bulayev, deputy chairman of the commission, said in a televised meeting there were problems with Mr Nadezhdin's paperwork.
"When we see dozens … of people who are no longer on this earth, and yet they have signed, questions of integrity and ethical norms that are used by signature collectors arise and the candidate is directly implicated to some degree," he said.
Already two other prominent potential candidates, anti-war liberal and former TV journalist Yekaterina Duntsova, and the jailed pro-war former militia commander and Putin critic Igor Girkin, have been prevented from running.
Mr Nadezhdin argues the election commission is not independent.
"The real decision for my registration is not the decision of the Central Election Commission. It is a decision of the Kremlin, of course."
Mr Nadezhdin claims that after he announced he wanted to run for president he was banned from Russian TV, which he describes as "controlled by the Kremlin administration".
He says that if he is allowed on the ballot paper, under electoral law they will have to put him back on TV during the campaign, exposing his anti-war views to millions of voters.
"The more people hear me, it's a great problem [for the Kremlin]," he says.
The risks of running against Putin
Things often end badly for political opponents of Mr Putin.
In 2020, Alexei Navalny survived a poisoning attempt with the nerve agent Novichok. The following year, he was arrested and eventually sentenced to 19 years in a penal colony.
Vladimir Kara Murza survived two poisoning attempts. In 2022, he was arrested after conducting an interview on CNN where he described Mr Putin's administration as a "regime of murderers".
He was charged under new wartime laws that forbid spreading "false information" about the military in relation to speeches he made criticising the war in Ukraine. Other charges, including treason, were added and he was sentenced to 25 years in prison.
In 2015, former deputy prime minister Boris Nemtsov was gunned down on a bridge near the Kremlin, days before he was due to lead a protest against Russian attacks on Eastern Ukraine.
Mr Nadezhdin is not naive about the risks of running against Mr Putin and he says he consulted with his family and people close to him before deciding to stand.
"I understand the risks, but I am not Boris Nemtsov. Boris was my close friend. I worked with him closely for seven years. And I am not Alexei Navalny.
"I never criticised Mr Putin personally like a man. I criticise him like the leader of the state. Only this way I criticise his politics, but I never criticise him personally.
"Unlike him [Navalny], I worked with Putin. I worked with Mr Kiriyenko, who is now one of the main people in the administration."
Sergei Kiriyenko is considered Mr Putin's mastermind of domestic politics. Mr Nadezhdin once worked as his aide and the pair have been close in the past.
That's led many to wonder if his campaign is not some kind of Kremlin set-up designed to make Russia seem like a functioning democracy.
Mr Nadezhdin denies his candidacy is a covert Kremlin operation organised by Mr Kiriyenko.
"Our last contact was when Mr Putin started to reform the Russian constitution. In 2020, the Russian constitution was dramatically changed [to allow Mr Putin to run again for president]. And I was against this.
"My good relations with the Kremlin administration finished in 2020."
In what might be considered further proof he is not linked to a Kremlin plot, Mr Nadezhdin told the ABC he has no faith that next month's presidential election will be a proper democratic ballot.
"Frankly speaking, we have no free and fair election," he said.
Elections in Russia are invariably mired in credible allegations of electoral fraud and other voting irregularities. Mr Putin has maintained his grip on power since 2000, as either president or prime minister.
If he is allowed on the ballot, Mr Nadezhdin does not think he can win this time around, but he believes he is tapping into growing anti-war sentiment, particularly among younger voters.
"If you ask young people, less than 30 years old, there is little support of Putin and little support of the special military operation," he said.
There is also a growing anti-war movement among the wives and mothers of mobilised soldiers, who have lobbied the Kremlin with petitions and protests.
Every weekend for several weeks, the women have held protests outside the Kremlin walls. Mr Nadezhdin has met with these wives and mothers.
"I am a councilman in the city of Dolguprudny for more than 30 years," he said.
"These women, my voters and their sons or husbands, who are in the battle, are my voters too.
"So I have contact with them, of course. And I know personally because from my election district, about 300 people were taken for this special military operation."
Last week, Russian TV's pro-Kremlin propagandists began criticising Mr Nadezhdin's candidacy, a sign that perhaps he is suddenly considered a threat.
State TV host Vladimir Solovyov described the collection of signatures on behalf of Mr Nadezhdin as an operation that would activate Ukrainian special forces on Russian soil.
"Who is this candidate from?" he asked. "From Ukrainian Nazis? Boris, aren't you ashamed?"
Mr Nadezhdin is expected to find out this week whether the Central Election Commission will allow him to run.