Ukrainian film director Oleg Sentsov looks out from the defendants’ cage during a hearing at a military court in Rostov-on-Don, Russia, in July 2015. (Sergei Venyavsky/AFP/Getty Images)

On Monday, the Ukrainian film director and Russian political prisoner Oleg Sentsov entered the fourth week of his hunger strike. Sentsov, who is being held in the Polar Bear penal colony in the Yamalo-Nenets Autonomous District in the far north of Russia, more than 3,000 miles from his native Crimea, has refused food since May 14. He is demanding the release of 64 Ukrainian political prisoners held in Russian custody. (He is not demanding his own.) Last week the prison administration placed him under medical supervision.

“Mr. Sentsov was detained for preparing terrorist attacks,” Russian President Vladimir Putin snapped last week after a reporter asked him about the prisoner at a news conference with French President Emmanuel Macron. The “terrorist attack,” if one is to believe the official story from Russian prosecutors, consisted in setting fire to the door of the Crimean office of Putin’s United Russia party. For this act — which he denies having any involvement in — Sentsov was sentenced to 20 years in prison. This is the same as the sentence given to the man convicted of assassinating Russian opposition leader Boris Nemtsov.

Sentsov’s real “crime” was his outspoken opposition to Putin’s annexation of Crimea in 2014. He has been recognized by Russia’s Memorial Human Rights Center as a political prisoner. Amnesty International has called his trial “unfair.” The Russian authorities have denied Senstov consular access by Ukrainian diplomats, claiming that, since Crimea is in their eyes (and in flagrant violation of international law) now a part of the Russian Federation, he is consequently a Russian citizen. Leonid Gozman, a political analyst, compared this to the de facto restoration of serfdom, when people were sold along with the land on which they lived. “This was normal practice before 1861,” he noted. “An estate lost in a card game would be transferred to its new owner along with the barns, the women, the men, and the other property. [Czar Alexander II] put an end to this, but who cares about him?”

Over the weekend, rallies in support of Sentsov were held in 78 cities around the world. Parliamentarians, diplomats and leaders of nongovernmental organizations were among those who joined the movement, calling on the government of Canada, the host of the upcoming Group of Seven summit, to put Sentsov on the agenda. In Moscow, the authorities have banned the pro-Sentsov rally on the grounds that it would “impede the movement of pedestrians,” but people came anyway. Prominent Russian cultural figures, including film directors Andrei Zvyagintsev and Vladimir Mirzoyev, writer Viktor Shenderovich and actor Alexander Filippenko, joined public calls in support of Sentsov.

“It is very easy for me to count the days Sentsov has been on hunger strike, I heard about it on the radio the day of my arrest,” wrote anti-corruption campaigner Alexei Navalny, who is in jail for organizing street protests against Putin’s inauguration. “I have been in detention for a week, and he has been on a hunger strike for a week. Fifteen days have gone by for me — so they have for him. Except we have a very different future ahead of us. Another fifteen days will pass, and I will be released, will hug my family, take a shower, and eat a home-cooked meal. Sentsov will die, alone in his cell, thousands of kilometers away from his family.”

The last political prisoner in Russia to die on hunger strike was Anatoly Marchenko, a prominent dissident and member of the Moscow Helsinki Group. Held in Chistopol prison, he began a hunger strike in August 1986 demanding the release of Soviet political prisoners. He died in December, after 117 days of refusing food. His family was not given a death certificate and was forbidden from taking his remains to Moscow for burial; he was interred in the local cemetery in Chistopol, with his wife writing his name on the cross with a ballpoint pen.

Marchenko’s death caused an international outcry. A week after he died, Soviet leader Mikhail Gorbachev telephoned Andrei Sakharov in Gorky to tell him that his exile was over and that he was allowed to return to Moscow. In January 1987 the Soviet government began a mass release of political prisoners. “Marchenko’s heroic life and his works represent an enormous contribution to the causes of democracy, humanism and justice,” Sakharov wrote to the European Parliament in 1988, nominating Marchenko as the inaugural (posthumous) winner of the Sakharov Prize for Freedom of Thought.

Navalny is calling on the Kremlin to effect an “all for all” swap, exchanging Ukrainian prisoners held in Russia, including Sentsov, for Russians seized by Ukraine in the Donbas war. “The Russian authorities are not interested in the opinion of Russian citizens,” said Alisa Ganieva, a novelist and the organizer of the pro-Sentsov rally in Moscow. “But if Western media talk about Sentsov, perhaps it will be uncomfortable for them. Perhaps international pressure will compel them to release him.”

International pressure is now the only force that can alter the Kremlin’s calculus — above all, pressure from those Western leaders who, like Macron, are planning to attend the upcoming FIFA World Cup in Russia. Even if they help Putin with his PR coup, they will at least have the comfort of knowing that they may have saved a human life.