The Russian prison service announced on Friday that Alexei Navalny, the most formidable opponent of Russian President Vladimir Putin, collapsed and died after a walk at the “Polar Wolf” Arctic penal colony where he was serving a 30-year jail term. The death of Navalny, a former lawyer, leaves the Russian opposition without its most courageous leader as Putin prepares for an upcoming election that could keep him in power until at least 2030. Navalny, who gained prominence by exposing what he saw as widespread corruption among the politicians running Putin’s Russia, was pronounced dead after losing consciousness during a walk at the penal colony. His wife, Yulia, expressed suspicion that the Russian government may be lying about his death. Western leaders paid tribute to Navalny’s bravery as a fighter for freedom and some accused the Kremlin of murder, holding Putin accountable for the death. Navalny’s movement was outlawed, and most of his senior allies now live in exile in Europe. Navalny had returned to Russia in 2021 from Germany after being treated for what Western laboratory tests confirmed as an attempt to poison him with a nerve agent. Navalny’s death is seen as a tragedy by many who had hoped he would one day take the Russian presidency. He had warned that Russia faced political turmoil due to a system of personal rule built on corruption and predicted that the country would have another chance at reform. The Kremlin dismissed his accusations of corruption and about Putin’s personal wealth and portrayed Navalny as an extremist and puppet of the CIA. Navalny had been arrested during protests against Putin in 2011 and had previously expressed that he was not afraid to challenge the Russian system despite the dangers.