Shortly after Russia shocked the world by attacking Ukraine on Feb. 24, Ilya V. Yashin, a neighborhood Moscow councilman and distinguished opposition determine, determined it was time to see a dentist.

The Kremlin was within the means of criminalizing criticism of the warfare, and Mr. Yashin, a really vocal critic, had determined to remain in his house nation and proceed to oppose President Vladimir V. Putin. Ultimately, he reasoned, jail time was extremely doubtless.

“I’m actually petrified of dentists,” Mr. Yashin mentioned in a current interview on YouTube, “however I received ahold of myself and did it as a result of I noticed that if I ended up in jail, there wouldn’t be any dentists there.”

Two weeks after the interview was printed, Mr. Yashin, 39, was certainly arrested. He’s now in pretrial detention in Moscow, on expenses of “disseminating false info” in regards to the warfare. He faces a sentence of as much as 10 years.

Mr. Yashin’s arrest highlights the quickly constricting avenues for dissent inside Russia as Mr. Putin cracks down on any divergence from the official narrative of the invasion. Past that, it has reignited the controversy among the many Russian opposition over how main figures like Mr. Yashin can finest serve the reason for undermining Mr. Putin: outdoors the nation they wish to reform, or inside a penal colony?

Mr. Yashin stays satisfied he made the correct selection. “What crime did I commit?” he requested rhetorically in a handwritten letter from jail to The New York Instances. “On my YouTube channel, I criticized the particular navy operation in Ukraine and overtly referred to as what’s going on a warfare.”

However some opposition figures disagree, saying that staying and combating may appear brave, however that jail is an ineffective platform for pushing reforms.

“Yashin is fearless — he’s a fighter, he’s courageous,” mentioned Dmitri G. Gudkov, a Russian opposition chief who left Russia final yr. “I’m positive that he won’t again down,” he continued. “However I’m simply unhappy that he’ll waste his life. It’s not comprehensible.”

Mr. Gudkov went into exile after what he described as “credible threats” {that a} prison case towards him would end in jail time. He mentioned he had inspired Mr. Yashin, a longtime buddy, to enter exile as effectively.

Yevgenia M. Albats, a journalist and buddy of Mr. Yashin who additionally determined to remain, took the alternative view, saying it was unattainable to have interaction in politics significantly from overseas.

“You can’t be a Russian politician in New York, in Manhattan,” Ms. Albats mentioned in a telephone interview from Moscow. “You can not name your self a Russian politician and be in London.” Nonetheless, she conceded, “The dangers are very excessive and they’re getting greater.”

Mr. Yashin acknowledged as a lot within the YouTube interview posted shortly earlier than his arrest, with the Russian journalist Yuri Dud. “I perceive that every day could possibly be my final one as a free man,” he mentioned.

He later wrote on social media that he believed it was his clear refusal to depart, expressed in that interview, that resulted in his arrest.

In his letter to The Instances, which was scanned and despatched final week, Mr. Yashin wrote that Russian “prisons are swiftly filling with political prisoners” as a result of Mr. Putin feels threatened.

“These harsh repressions,” Mr. Yashin wrote, “not directly verify that the present navy marketing campaign is devoid of legitimacy.”

Mr. Yashin knew his outspokenness and his platform would make him a goal, and buddies agree that his detention was solely a matter of time. He had been repeatedly fined for “discrediting” the Russian navy — principally by speaking about different wars. In April, he shared a well known {photograph} of girls protesting the Vietnam Warfare in 1969, saying that the hypocrisy behind the rationale for the warfare, expressed within the slogan “bombing for peace,” remained current immediately.

He was additionally fined in Might for citing a condemnation of Russia’s invasion of Afghanistan by Andrei Sakharov, the primary Russian to be awarded the Nobel Peace Prize, and the well-known phrases of a Soviet bard who raised alarm in regards to the invasion of Czechoslovakia in 1968.

After the invasion started in February, he continued to name out Mr. Putin’s authorities, holding common livestreams on his YouTube channel criticizing the facility of the safety providers in Russia. He additionally documented a go to to the penal colony holding essentially the most distinguished Russian opposition determine, Aleksei A. Navalny, and made reference to a BBC report about Russian atrocities in Bucha, the premise of his cost for distributing false info.

The one selections open to opposition politicians from Russia immediately are “emigration or jail,” mentioned Lyubov Sobol, who was pressured to to migrate after her boss, Mr. Navalny, survived an tried poisoning, returned to Russia and was instantly arrested. It was on Mr. Navalny’s recommendation that Mr. Yashin went to the dentist.

Mr. Navalny has remained influential in jail. The big workforce that he assembled earlier than his arrest has reconstituted overseas. Observers say sustaining such a public profile from jail requires a big equipment like Mr. Navalny’s; Mr. Yashin has up to now been in a position to smuggle out messages later posted to social media.

Ms. Sobol, a lawyer, mentioned she couldn’t criticize a colleague whereas he was in jail. However she mentioned nobody in Russia may fill in for Mr. Yashin, on YouTube or within the political area.

“He had an enormous YouTube channel, a big viewers, which trusted him,” she mentioned of Mr. Yashin, who has 1.3 million subscribers. “I do know many individuals who despatched his movies to their grandparents. And so they modified their minds about Russian propaganda, as a result of he spoke quite simple, vibrant and good language.’’

“There are not any different folks” in Russia in a position to do this proper now, she mentioned.

Mr. Yashin turned lively in politics when he was 17, simply as Mr. Putin got here to energy, and shortly rose to steer Moscow’s chapter of the youth wing of the liberal Yabloko get together. When Yabloko reprinted a Russian translation of George Orwell’s dystopian novel “Nineteen Eighty-4,” Mr. Yashin wrote the introduction, warning that the “period of Huge Brother” had begun in Russia.

He ultimately turned shut with the opposition politician Boris Nemtsov, who was shot lifeless in Moscow in 2015 by assassins believed to be linked to Ramzan Kadyrov, the strongman who has led the Russian area of Chechnya since 2007. Across the time of his homicide, Mr. Nemtsov was compiling a report on the involvement of Russian troopers within the warfare that had begun in japanese Ukraine in 2014. Mr. Yashin completed and launched the report, and have become one of many few politicians keen to overtly criticize the Chechen chief.

In 2017, Mr. Yashin and fellow opposition candidates gained seven out of 10 seats on the native council within the Krasnoselsky district of Moscow.

As council head, Mr. Yashin addressed quotidian issues: playgrounds, parking, gentrification. He repurposed his official automobile and driver as a free taxi for the district’s disabled. On YouTube, he delivered common reviews in regards to the council’s achievements and challenges. He referred to as out the corruption of presidency businesses and subcontractors.

Dealing with fixed scrutiny from the prosecutor’s workplace, Mr. Yashin stepped down as council head in 2021, mentioned Yelena Kotenochkina, who took over council management.

Prosecutors “have been always checking what we have been doing,” she mentioned. Mr. Yashin’s repurposing of his official automobile prompted an investigation for abuse of energy.

In March, one other council member, Aleksei A. Gorinov, urged the district shouldn’t maintain a youngsters’s occasion celebrating the Soviet victory in World Warfare II whereas youngsters have been dying in Ukraine. Ms. Kotenochkina agreed. On the finish of April, each have been charged beneath the “false info” legislation. Ms. Kotenochkina managed to flee to Lithuania; Mr. Gorinov was sentenced to seven years in a penal colony.

Ms. Kotenochkina mentioned the case towards her and Mr. Gorinov had been a “trace” to Mr. Yashin that he ought to go away the nation or face jail.

And late one June night, Mr. Yashin was detained as he walked in a park with a buddy, the unbiased journalist Irina Babloyan. He was accused of disobeying police orders — a bogus cost, insisted Ms. Babloyan — and sentenced to fifteen days in jail. As quickly as he was launched, he was arrested once more on the false info cost, and now awaits trial. Final week, Russian authorities labeled him a “overseas agent,” a authorities label tantamount to enemy of the state.

“Now folks see: We’re not working anyplace, we stand our floor and share the destiny of our nation,” he wrote.

“This makes our phrases price extra and our arguments stronger. However most significantly, it leaves us an opportunity to regain our homeland. In spite of everything, the winner isn’t the one who’s stronger proper now, however the one who is able to go to the tip.”

Alina Lobzina contributed reporting.