How does one destroy a Republic? You destroy the very notion of res publica.
You convince the people that there is… no People. No civic space. No public forum. Every square inch of the planet, owned by someone. Every idea, every invention, every thought, every human creation of value, owned by someone.
Every one of us… well, owned, by someone.
You convince them that the notion of banding together in their own common interest is naive and stupid at best, or insidious and evil at worst.
You leverage almost a century’s worth of social engineering to peel away at their very human pieces. Commoditize their religions, their politics, their stories, their History, their fictions. Their dreams.
Train them to identify with some abstract Tribe (their innate biological wiring predisposes them to it, after all) and to instinctively distrust, despise anyone or anything Other. Offer them a limited buffet of (so-called) “Lifestyles”, and they will happily choose, and thank you for the right to do so. Train them to speak in social codes, shibboleth, images, feelings, symbols that are unique to each tribe, until they lose the ability to even communicate across the artificial semiotic fences you’ve built for them.
Give them idols to worship– artists without art. Leaders without leadership. Gods without… godliness. Give them joyless, pointless festivals and rituals to keep them busy, and so they can feel as though they belong. Keep them just well fed enough that they won’t revolt (but not too well– be sure to keep just enough of the poor around to keep the others in permanent fear of losing what little they have).
You convince them that this is the only World. That they are without hope of escape, or improvement, or that the very notion of the possibility of ‘progress’ in the classical sense is a naive illusion, or delusion (and make sure you train them how to laugh at those who do, while you’re at it). That Power is all. That Money is all. That they are nothing more than meat to be cultivated, bought and sold, and finally consumed.
Until one day, they have nothing left but fear and ignorance; distrust and hatred. The useful submission that comes from Quiet Desperation.
You train them to act as their own prison guards, essentially. No need to censor (or censure), at least not publically. Keep the forums open and free, and let the little people speak as much as they want. For have no fear, the others will gladly shout them down.
Black Iron Prison, indeed. Only this time around, enclosed within a Cage of Velvet Rope.