When the Soviet Union fell, it seemed the Soviet attempt to impose a deluded version of reality had died with it. Francis Fukuyama, in his 1989 essay “The End of History,” said that Marxism-Leninism was doomed as an alternative to liberal democracy. I argued at the time that the drive to make a religion out of politics had not disappeared.

For the past four years, potted histories have warned about the rise of fascism in the U.S. But the real danger is the transformation of “tolerance” into an ideology with its own courts, informers and punishments, all of them reminiscent of the Soviet Union.

One of the pillars of the Soviet Union was a controlled press in which all coverage was organized to confirm a mendacious ideology.

A friend of mine in Moscow, Vladimir Fyodorov, went to work for the TASS news service, which offered readers not news but a “correct” depiction of events, especially regarding the U.S. and the “ulcers of capitalism”—racism, crime and unemployment.

On his first day at TASS, Vladimir was handed a United Press International story about a U.S. company that was promoting a high-quality tire and offered to replace older tires free of charge. Vladimir wanted to kill the story but his boss rewrote it. The new version read: “In the crafty capitalist market, firms frequently offer low-quality products. This is why a well-known American firm was forced to replace tires that were of inferior quality.” The headline was “Deception of Buyer.”

A few weeks later, Vladimir was given a report that prisons in Fiji were so comfortable that people preferred to stay there than to be at liberty. He produced a report that life in Fiji was so unbearable that people preferred to live in prison. His colleagues congratulated him. He told himself: “I’m going to go out of my mind here.”

Soviet practices would have once been unthinkable in the U.S. media. But in August 2016, Jim Rutenberg, media columnist for the New York Times, wrote that if journalists believed that Mr. Trump was a “demagogue playing to the nation’s worst racist and nationalist tendencies,” it was necessary to “throw out the textbook of American journalism.” The Times started to characterize Mr. Trump’s statements as “lies” in news stories and suppress news that worked to Mr. Trump’s advantage, such as the Hunter Biden story this fall.

The Times also advanced an ideological account of U.S. history, according to which the American Revolution was undertaken to defend slavery, and promoted it over the objections of historians and the paper’s own fact-checkers.

The Soviet system also relied on the complete liquidation of academic freedom. Marxism-Leninism was treated as a perfect science. But the ideology raised obvious questions: In a “classless society,” why were there special stores for officials? If socialism ended war, why did the Soviet Union and China go to war in 1969 over Damansky Island?

If a student tried to raise these questions, he was expelled from the Komsomol, the communist youth league. That ended any hope of a career. I knew a young man in Moscow who refused to be intimidated and continued to ask questions. He was committed to a mental hospital.

The Soviet style has become a reality in the U.S. Speakers are routinely canceled on ideological grounds: In July the College of the Atlantic in Bar Harbour, Maine, canceled a virtual talk with Leonard Leo of the Federalist Society because of “the moment of reckoning our society is going through.” At my alma mater, the University of Chicago, the English department announced that it would “only accept applicants interested in working in and with Black Studies.”

The Soviet Union finally counted on the readiness of people to betray even family and friends. The regime held up Pavel Morozov (1918-32) as a martyr. He lived in a village in the Urals when the regime was collectivizing agriculture. When Pavel learned that his father was helping peasants hide grain, he walked 35 miles to the nearest town to report him to the secret police. His father was arrested and Pavel was stabbed to death by relatives.

I thought of Pavel Morozov when I read a June op-ed in the New York Times by Chad Sanders, a black writer. He told his white friends that he didn’t need their “love texts” and suggested that instead they cut off contact with family members until they sent money to Black Lives Matter or joined their protests.

When Mr. Gorbachev began the reforms that destroyed the Soviet Union, he said, referring to the U.S.: “We’re going to do something terrible to you. We’re going to deprive you of an enemy.” Twenty-nine years later, it’s clear he was right. Without the ideological challenge of the Soviet Union, we have become immersed in internal conflicts and have made an ideology out of them.

It is true that Marxism is a more coherent system of thought than “wokeism.” But even an intellectual hodgepodge can engender totalitarian habits if it fulfills an emotional need and becomes a device of interpretation.

The antidote is fidelity to higher values. But that requires a moral seriousness that a world at peace and in thrall to superficialities does not inspire. “The West does not know and does not want to know what shaped it,” writes Cardinal Robert Sarah, a Guinean prelate. “This self-asphyxiation leads to new barbaric civilizations.”

The Soviet Union is dead, but its ghost wanders an unsettled world. Finding a lodestar for society’s moral development is the most important challenge facing the U.S. today.

Mr. Satter is author of “Age of Delirium: the Decline and Fall of the Soviet Union” and a member of the academic advisory board of the Victims of Communism Memorial Foundation.