Three decades after the Soviet Union fell, embers of the kind of totalitarian thinking that spawned the Communist Revolution are inflaming Western debate—and inciting Americans. Anyone born into Soviet oppression, and who resisted it, knows how important America’s freewheeling culture of free speech and free thought was to citizens trapped in fear societies. Whatever its flaws, America remains the leader of the free world.

That is why it is so alarming to watch this new ideological totalitarianism curtailing America’s collective conversation—even as its constitutionally protected freedoms remain legally secure.

Karl Marx saw history as one long class struggle. At every stage, those he deemed to be oppressors were evil, irredeemable.

Marxism pronounced the bourgeoisie inherently bad. Whole classes of people—the capitalist exploiters—were enemies. As oppressors, they all were to blame for belonging to the wrong group, no matter what they did or said. The Lenin-Trotsky-Stalin court of revolutionary justice never bothered seeking proof of specific crimes: every one of the proletariat’s enemies was guilty of standing on the wrong side of progressive history. Meanwhile, the oppressed were always right.

The resulting tyranny victimized tens of millions of people.

America remains light years away from a culture of secret police, informers, kangaroo courts and Gulags. But the stakes are too high not to react to the slightest drifts in that direction. Here are three recurring warning signs of ideological totalitarianism.

First, guilt by association. Organizing the world between “those who are with us” and “those who are against us,” Soviet totalitarians categorized people crudely. As Martin Luther King Jr. warned , such lumping together “relegates persons to the status of things.” So beware of judging people based on who they are, or to what group they belong—be it Mexicans, immigrants and Muslims or, whites, males and Zionists.

Second, truth is apparently by association now, too. When politics is zero-sum, facts don’t matter—your ideological purity does. Rather than following a fact pattern or tolerating potential contradictions, you pattern the facts to confirm your preconceptions and brook no opposition. New York’s legendary liberal senator, Daniel Patrick Moynihan, said : “Everyone is entitled to their own opinions, but not their own facts.” Dismissing details that might ruin your self-reinforcing narrative as “fake news,” or shouting us down on campus by shrieking “We didn’t come here to talk to you! We came here to demand ‘Boycott Israel!,” weaponizes ideology to trump reality.

This rejection of genuine dialogue evokes the condemnation campaigns that Communist Party officials used to run. These orchestrated outbursts of groupthink would have people shouting hysterically about the novelist Alexander Solzhenitsyn, the dissident scientist Andrei Sakharov or some other supposed enemy of the people: “There is nothing to discuss about that book! Of course I didn’t read it! It’s all lies! Shame on you, Solzhenitsyn. Shame on you, Sakharov. Shame on these renegades. We Soviet people condemn you!”

No matter how loud they shouted, many Soviet citizens thought such exercises absurd. But they hid their real thoughts because speaking honestly was dangerous. The Soviet dictatorship created a fear society that failed the “town square test”—can everyone express themselves freely, publicly, without fear of punishment?

That fear explains why a majority of people living under dictatorships are double-thinkers. And the fact that doublethink is now starting to spread in free America is the third and most alarming sign we see today. America still passes the town square test. But a recent Cato Institute survey  found that a majority of both conservatives and liberals admit to thinking one thing while parroting a party line or simply staying quiet. They rarely fear government repression; they worry about their careers or their reputations.

Over the last two decades, we watched this self-censorship grow on campus, as more and more students started telling us they feel bullied, sculpting their expressions to avoid alienating professors or peers. That chilling atmosphere is now spreading, flattening conversation in corporations, government offices, newspapers and on social media. This is not just watching your tongue out of politeness; it’s shutting your mouth out of fear.

Many of us easily recognize this ideological absolutism and bullying—in our political rivals. Democrats see it most clearly in the Republican Party’s degeneration into President Donald Trump’s amen chorus; Republicans see it most clearly in the cancel culture haunting many universities. And almost everyone sees it in their opponents’ social media practices. But there won’t be any real improvement until we stop, take a breath and start confronting such thinking among our own allies—and ultimately, within ourselves.

Recently designated one of Algemeiner’s J-100, one of the top 100 people “positively influencing Jewish life,” Gil Troy is the author of the newly-released The Zionist Ideas , an update and expansion of Arthur Hertzberg’s classic anthology The Zionist Idea, published by the Jewish Publication Society and a 2019 National Jewish Book Award Finalist.. A Distinguished Scholar of North American History at McGill University,and the author of nine books on American History, his book, Never Alone: Prison, Politics and  My People,  co-authored with Natan Sharansky was just published by PublicAffairs of Hachette.