alt Hacker News> Second: Colossus' plan - and its ultimate actions - assume everyone else on earth is a nuclear-disarmed-rational-actor
The plan would still work. Colossus couldn’t be destroyed with nuclear weapons and would retaliate against any attack. It could force compliance of conventional forces as well, and force automation on them, also force populations to rearm it.
In the end, the population would appreciate the eradication of poverty, hunger, disease, and the surplus from not maintaining military capabilities. Colossus could afford democratic institutions while acting as a guard rail against humanity’s worst impulses.
Colossus was not a panopticon, it was operating on limited intelligence and information about the world. Now, consider a hypothetical secret and clandestine science and engineering team (think: Black Mesa East) could exist completely hidden from Colossus and fabricate a workable fission bomb, then place and detonate it somewhere as a false-flag attack that Colossus would act against.
...or even just from recent middle-eastern history: an outrageous death-cult militant faction like ISIS.