As his campaign of aggression continues in Ukraine, Russian President Vladimir Putin has been put on public notice by a high-profile political opponent who suggested Friday that the dictator is likely to be toppled sooner rather than later, as the Daily Mail reports.

 The words of warning came from Ilya Yashin, a well-known critic of Putin and of the war in Ukraine, as he was sentenced to eight and a half years imprisonment on charges of disseminating false information allegedly designed to undermine the Russian army via multiple posts regarding the treatment of Ukrainian civilians at the hands of Russian troops, according to the U.K. Guardian.

 Dissident's words of warning

Yashin, 39, who is also an ex-boyfriend of a woman said to be Putin's goddaughter, Ksenia Sobchak, issued his prediction after learning his fate in the case that yielded the most notable conviction yet under new rules making criticism of the Ukraine war a criminal offense.

Smiling and waving despite the unenviable outcome in court, Yashin addressed those who turned out to show their support for his outspoken activism, proclaiming, “Don't get upset, it's ok.”

“If anyone thinks that Putin will rule for eight years, he is a very big optimist,”  Yushin further declared.

 The activist's words were met with applause from supporters present in the courtroom, something for which Yashin's own father, Valery, expressed gratitude.

“Even strangers were approaching and saying words of support. This is very precious to us,” said Mr. Yashin.

Crackdown continues

The trial of Yashin was the product of a new legal framework instituted in February criminalizing speech Russian authorities determine to be false or damaging to the country's military forces.

In court on Friday, the verdict against the vocal Putin opponent read, “Expressing hatred of the political system of the Russian Federation and realizing that he is a public person … Yashin created a real threat to the formation of a negative attitude towards the armed forces of the Russian Federation.”

Yashin stood firm in the face of those rules, however, remaining in Russia as the Ukraine war progressed and giving voice to his disagreements with Putin.

As part of his closing statement in the criminal case, Yashin implored Putin to “immediately stop this madness,” as the Daily Mail noted.

“We need to recognize this policy towards Ukraine is wrong, to withdraw troops from its territory and move on to a diplomatic settlement of the conflict,” Yashin continued, vowing, “I will not give up the truth even behind bars.”

Sentence slammed

The conviction and sentencing of Yashin drew swift condemnation from his ally and fellow opposition activist Alexei Navalny, according to the Daily Mail.

“Another shameless and lawless verdict from Putin will not silence Ilya and it should not intimidate Russia's honest people,” Navalny wrote on Instagram soon after the conviction was announced.

Sobchak expressed similar outrage over the result, deeming the prison sentence “terribly unfair, monstrous,” lauding her former love interest as “noble...in his fidelity to principles,” and praising his “courage in the face of the abyss.”

Precarious position

Rumors of a possible coup against Putin from within have persisted for months in light of the unexpected success of Ukrainian resistance efforts, and back in May, at least one expert on the inner workings of the Kremlin went so far as to predict that an overthrow of the dictatorial leader within three months was increasingly probable.

Despite those prognostications, Putin has stubbornly managed to remain at the helm, continuing to pursue his territorial ambitions in the face of repeated and serious setbacks.\

In the end, however, Putin's exit from power may not be the result of the sort of forceful ouster Yashin seems to expect, but may instead be brought about by one or more of the serious health conditions from which he is rumored to suffer, such as Parkinson's disease and pancreatic cancer, but only time will tell.