4 ideas
It is true that Stalinism was present in germ in early Bolshevism, but Bolshevism also contained other germs: soviet democracy, internationalism, and self-sacrifice. Which germ grows is decided by later circumstances and choices, such as isolation, famine, civil war, and the rise of a bureaucracy. Reading outcomes backward as inevitable erases the real forks where a different path was possible.
The Bolsheviks created the Cheka, an emergency commission that could judge in secret with no defense and no public accountability. Serge argues this was their gravest mistake, because an unchecked apparatus of repression selects for people who are suited to it. It outlives the emergency that justified it and turns against the revolutionaries themselves. Terror used to protect a revolution becomes the thing that destroys it.
Old Bolsheviks confessed to absurd crimes at the Moscow Trials. Torture alone does not explain this. They had fused their personal identity with the party, so breaking with it felt like annihilating their whole life's meaning. The same devotion that made them effective revolutionaries made them unable to resist a party that demanded their self-destruction.
In 1933 Serge was arrested for his Left Opposition sympathies and deported with his young son to Orenburg in the Urals, where they lived near starvation. Writers in the West, especially in France, campaigned for him, and the issue was raised publicly, including with Romain Rolland. In 1936 the regime expelled him from the USSR rather than let him disappear, but it confiscated his manuscripts at the border. Most Oppositionists without foreign reputations were later shot, which shows that international visibility could save individuals whom principle and innocence could not.