Natan Sharansky, the legendary Soviet refusenik who survived nine years in the Gulag, has often described the three social divisions that exist in dictatorships ruled by fear.

There are “true believers” who embrace the ideology of the regime and loyally support its policies. There are “dissidents” who reject the government’s claims, condemn its repression, and speak the truth despite the risk of punishment. But the largest group is composed of “doublethinkers” — people who know that their nation is ruled by criminals and liars but are scared to say so openly. Doublethinkers engage in continual self-censorship, parroting the official line in public and revealing their true beliefs only with family and trusted friends.

Yet over time, tyranny turns doublethinkers into dissidents. Tyranny — plus the inspiring example of courageous dissidents.

Sharansky himself was one such dissident.

Alexei Navalny, who died last month under suspicious circumstances in an Arctic prison camp, was another.

The charismatic reformer and resistance leader was a rarity: a Russian politician intrepid enough to challenge President Vladimir Putin. Navalny nearly died four years ago, when he was poisoned with the nerve agent Novichok — a lethal compound that Russian agents have used to assassinate other dissidents. Miraculously, he survived. He was airlifted to Germany, where doctors neutralized the toxin and restored him to health. Whereupon, with a heroism few of us could muster, Navalny returned to Russia, knowing full well that he was going to his doom. He was arrested by Putin’s agents as soon as his plane landed in Moscow. Three years later, he is dead at 47.

The cause he fought for, however, lives. Navalny’s lionhearted strength is turning more doublethinkers into dissidents. Thousands of Russians attended his funeral and burial in Moscow on Friday, filing slowly past his casket in defiance of the Kremlin’s warning that anyone attending a gathering to memorialize Navalny “will be held accountable.” It was no idle threat. More than 400 people were arrested across Russia in the days following his death, many for simply laying flowers or lighting candles in his honor. But the courage of dissidents is infectious.

On the street outside the church where the service was held, crowds called out Navalny’s name and chanted, “Don’t give up! Don’t give up!” One woman told The Wall Street Journal: “We were very afraid. We arrived early and were standing here for a long time hiding our flowers and cameras. But now I realize that we need to do this and speak up.” Such is the power of dissent in repressive societies.

In a remarkable exchange last year, Navalny sent a handwritten letter to Sharansky from his isolation cell, having read the older man’s prison memoir, “Fear No Evil.” Quoting a phrase from Sharansky’s book, Navalny wrote that like all dissidents he carried the “virus of freedom.” He was confident that whatever might happen to him, that virus would spread. “It is no longer tens or hundreds as before, but tens and hundreds of thousands who are not scared to speak out for freedom and against the war [in Ukraine], despite the threats,” he said. “Hundreds of them are in prisons, but I am confident that they will not be broken.”

In his reply, Sharansky described something he knew from personal experience — the power of a fearless dissident, even one locked away in a punishment cell above the Arctic Circle, to imbue others with the bravery to speak truth to power. “By remaining a free person in prison, you, Alexei, influence the souls of millions of people worldwide,” he wrote.

Speaking to reporters after Navalny’s death, President Biden hailed him as a principled champion of truth and lawfulness, describing his death as “yet more proof of Putin’s brutality.” Those words were fine as far as they went. But the time for political leaders in the West to focus on dissidents is when they are still alive and amplifying their message can weaken the despotic regimes that oppress them.

In The Economist last week, Sharansky urged Western politicians to revive the concern for dissidents that was so strong during the last years of the Cold War. During the Carter and Reagan administrations, the well-being of Soviet dissidents was elevated to a priority by US diplomats. Diplomats repeatedly raised the subject in meetings with their Kremlin counterparts. Policy makers “saw the fate of Soviet political prisoners as part of their own security,” Sharansky observed. “Now they don’t. And this is a mistake of historic proportions.”

Prisoners of conscience are among America’s most valuable potential allies. The leaders of the free world should be constantly speaking their names and expressing solidarity with their struggle. They risk their lives for the freedom we take for granted. They deserve to know that we have not forgotten them.