The camp system began under Lenin, not only under Stalin
Applebaum traces the Gulag's origins to the earliest years of Bolshevik rule, showing that mass detention of political and social "enemies" began under Lenin, well before Stalin's later dramatic expansion of the system. Within just a few years of the revolution, dozens of camps already existed across many provinces, built initially to hold aristocrats, merchants, and other people classified as threats to the new order.
This matters against the popular tendency to treat the Gulag as a purely Stalinist phenomenon, a personal creation of one dictator's paranoia. Applebaum argues instead that mass repression through camps was embedded in the revolutionary project from its founding moments, making the later Stalinist system an escalation of an existing logic rather than an entirely new invention.
Her point is not to exonerate Stalin, whose personal decisions drove the system's most extreme expansion, but to correct a historical shorthand that lets the earlier revolutionary period escape scrutiny for building the foundational infrastructure and legal mechanisms the later, larger system relied on. Takeaway: the machinery of mass forced detention predates Stalin and was built into the Soviet project from its earliest days.