Stuck in a provincial prison, Alexei Navalny can know at least that he is not forgotten. The Russian opposition leader has been unjustly incarcerated for nine months. The European Parliament on Wednesday awarded him the Sakharov Prize for Freedom of Thought, a prestigious honor for those who fight for human dignity and against dictatorship. The recognition should keep attention focused on Mr. Navalny, who was the target of an assassination attempt with a chemical weapon last year by the regime of President Vladimir Putin. Meanwhile, Mr. Putin's authoritarian system grinds on. The latest attempt to suppress an independent voice is one of the most alarming and fundamental yet, targeting the Moscow human rights organization Memorial, founded in 1987 to protect the memory of the deaths and misery caused by Soviet dictator Joseph Stalin, and to fight against abuses in the present day. Memorial is a conscience of the past and the present. On the evening of Oct. 14, Memorial sponsored a long-planned screening of Polish director Agnieszka Holland's 2019 historical drama, "Mr. Jones," which portrays British journalist Gareth Jones, who was the first to report on the Stalin-instigated famine in Ukraine in the 1930s. Because Memorial was designated a "foreign agent" by Russian authorities in 2014, it must ask official permission for the event, which was granted. Halfway through the screening, a group of rowdy thugs burst in and stood in front of the screen, disrupting the event and shouting slurs at the audience. Memorial called the police. They arrived quickly — and then let the thugs go, locked the doors and forced Memorial's employees to remain inside for interrogation. The police only left hours later, carting off Memorial's DVR. The next day, the police returned and demanded to inspect documents and confiscated computers. It was all blatant harassment. Memorial was established in the age of dissident Andrei Sakharov and Mikhail Gorbachev's early glasnost and perestroika, when hopes ran high that democracy would take root where Soviet communism had left a barren landscape. Memorial created and preserved a remarkable archive of Stalin-era repressions. It also has defended people against gross human rights violations in the present day. This work — documenting Stalin's horrific misdeeds and protecting against them now — discomfits Mr. Putin.