"[Bolsheviks] were the only apocalyptic sect that had ever taken over an “existing heathen empire”: they ruled over the population of the former Russian Empire, which was overwhelmingly ignorant of or unreceptive to their teachings. This required a proselytizing effort unparalleled in history; and when persuasion failed, coercion would have to follow, along with the isolation, exclusion and even extermination of the unconverted.

[..] Only one boy [, victim of his parent's persecution,] has what we might regard as the “natural” reaction: to rage at the Terror and denounce the Soviet government (including Stalin). A couple of others throw in their lot with the killers of the Old Bolsheviks and become informers and NKVD agents. But a surprising number continued much as before, reading and writing, forming intense friendships, and remaining attached to their notions of happiness and fulfillment. [..] For those Bolshevik children who were un­settled or tormented by their parents’ disgrace, there was soon an opportunity to achieve redemption and to emulate the exploits of the revolutionary generation. The Great Patriotic War of 1941–5 yielded nothing to the civil war in apocalyptic horror and exceeded it in the opportunities it afforded for righteous fury and self-sacrifice. Here, or so it appeared, were the deferred End Times that the interwar Old Bolsheviks had craved.

[..] Marx and Engels were not authors they read by choice. As the hold of scripture weakened, so did the spirit: the Bolsheviks’ sectarian intensity could not be maintained beyond a single generation. The Soviet Union, like any other theocracy that enjoys longevity, became a “priesthood”. But, in Slezkine’s analysis, even that priesthood could not maintain itself beyond a single human lifespan (1917–91), largely because it neglected matters of family life and morality to which traditional religions tended to devote minute attention. It turned out that the Bolsheviks were “not totalitarian enough”: agitation had stopped at the door to the single-family apartment.

[..] It was not that Bolshevism reached a dead end but that it was re-routed to the cause of imperial nationalism. As Slezkine describes, by the end of the Great Terror, and in fact sometime before, political language had become almost empty of referential meaning; it was impossible in empirical terms to draw the line between backsliding and “excesses” of zeal or to know in advance what “Lenin would say”. But language cannot remain meaningless forever, and geopolitics and Nazism provided a potent reality check.

[..] It almost goes without saying that Bolshevik politics was full of turf wars, vendettas, self-interest, cowardice and patron–client relationships; motivations were often baser and more pragmatic than anything in the Marxist-Leninist playbook, and sometimes more humane. But the Bolsheviks were also master rhetoricians, creating a unique brand of syllogistic storytelling that showed why the arrival of communism was not only desirable but impeccably logical. This did not make them con men: the first people they set about persuading of the nobility and in­exorability of their cause, despite all evidence to the contrary, were themselves. When they were sharing huts in exile in Siberia, they still understood that rhetoric and reality were some way apart. But when the brotherhood turned into a ruling class, language became detached from empirical referent, rhetoric became reality, and words became deeds."

https://www.the-tls.co.uk/articles/public/house-of-government-slezkine/