Communists around the world can take the great tragedy of the Soviet Union's fall, and turn it into a learning experience. We can study the decisions within the country's leadership that led to Washington succeeding in carrying out the 1989-1991 imperialist coup, and avoid the equivalent missteps as we go about our own revolutionary work.
What's a basic summary of why the USSR was unable to withstand imperialism's subversion efforts? Xi Jinping, who's far more learned in Marxism than I am, states it as follows:
Why did the Soviet Union disintegrate? Why did the Communist Party of the Soviet Union fall to pieces? An important reason is that in the ideological domain, competition is fierce! To completely repudiate the historical experience of the Soviet Union, to repudiate the history of the CPSU, to repudiate Lenin, to repudiate Stalin was to wreck chaos in Soviet ideology and engage in historical nihilism. It caused Party organizations at all levels to have barely any function whatsoever. It robbed the Party of its leadership of the military. In the end the CPSU""as great a Party as it was""scattered like a flock of frightened beasts! The Soviet Union""as great a country as it was""shattered into a dozen pieces. This is a lesson from the past!
Kim Jong Il, another great Marxist scholar, explained it similarly, saying that the USSR and the GDR fell because "they neglected class education and abandoned the class struggle. After assuming state power, Khrushchev weakened the function of the dictatorship of the state as a weapon of the class struggle. As a result, socialism could not be defended in the Soviet Union." In short, the Soviet power structure gave way to the pressure from the imperialist coup-mongers because the integrity of this structure had been systematically degraded. And it was degraded because the dictatorship of the proletariat had been abandoned.
This provides a pretty simple first lesson for Marxists: don't abandon the dictatorship of the proletariat (i.e. the workers' democracy) or let revisionist actors weaken its structure. But why was the revisionist Khrushchev camp allowed to carry out this attack on the integrity of the country's proletarian democracy in the first place? As Mao Zedong wrote, the narratives that this camp put forth to justify their actions were transparently phony and hypocritical: "The revisionist Khrushchov clique abolish the dictatorship of the proletariat behind the camouflage of the 'state of the whole people', change the proletarian character of the Communist Party of the Soviet Union behind the camouflage of the 'party of the entire people' and pave the way for the restoration of capitalism behind that of 'full-scale communist construction.'"
These lies were built upon a bigger, earlier lie. A lie that today's imperialist propagandists and anti-communist ideologues use an updated version of to argue for the dissolution of modern socialist states. This is the lie that Stalin was guilty of the series of atrocities that bourgeois propagandists accused him of, and implicitly that the Marxist-Leninist dictatorship of the proletariat which Stalin upheld needed to be thrown out in favor of something more "democratic." This was the narrative that stemmed from Khrushchev's "secret speech," which supposedly implicated Stalin in a myriad of crimes.
If you've encountered the types who accuse China of committing a "genocide" against Xinjiang's Uyghurs, who portray Kim Jong Un as an autocrat that regularly commits war crimes against his people, who portray Cuba as an oppressive "totalitarian" state which lacks democracy, who portray Vietnam and Laos as non-democratic, you surely see the modern parallels that I'm seeking to illustrate. Like how all of the claims from Khrushchev's speech have been shown to be verifiably false, all of these claims about modern socialist countries have been debunked or shown to be conjured out of thin air by malicious propagandists. But those who seek to undermine socialism continue to put them to use, for the same reason that Khrushchev and the imperialists who supported his anti-Leninist reforms put the false claims about Stalin to use.
What we're seeing in these modern anti-communist propaganda and subversion campaigns is nothing new. Washington went through all of them during the previous cold war. In the case of their mission to destroy the Soviet Union, the imperialists began by inventing lies about the designated communist bogeyman Stalin. Then when opportunistic-minded individuals within the Soviet leadership became willing to parrot these lies, the imperialists got these leaders to grant an excessive amount of concessions to the forces of capital (dismantling the proletarian dictatorship, partially restoring capitalism in Russia, etc). Then when these pro-capitalist reforms exacerbated the problems with Russia's economy that its great defensive military expenditures created, the imperialists portrayed this as proof that "socialism had failed" and stirred up counter-revolutionary elements which saw the economic situation as justification for dismantling the Soviet Union. Gorbachev was the final part of this murder by a thousand cuts.
Washington's problem is that now, the leaders of the five Marxist-Leninist nations China, Korea, Cuba, Vietnam, and Laos aren't buckling under the pressure like the USSR did. Xi Jinping isn't pushing for dismantling the proletariat dictatorship to prove to the imperialist propagandists that China is "democratizing," and the leaders of the other socialist nations also aren't doing anything similarly ridiculous. These nations are standing their ground in the face of perpetual slander against them, and are consequently making themselves better fit to preserve the integrity of their institutions.
In this way, you could say that the leaders of today's socialist states have learned from the mistakes of the Soviet leadership. Is this any surprise when I've been able to quote two major post-Soviet leaders of these nations, along with the great Marxist teacher Mao, in agreeing that Khrushchev was a revisionist? For those learned in Marxism enough to lead a socialist country, the mistakes that brought down the Soviet Union seem to be common knowledge.
As for communists who are working to overthrow the capitalist states that they live under, absorbing the same lesson will evidently be crucial for the long-term survival of their revolutionary projects. This lesson being that when you concede to the falsehoods that the imperialists promote, when you fail to speak out against anti-communist lies, these lies will work to undo you in an insidious fashion.