Flood the zone with christofascist, orthodoxy propaganda in almost every public and private distribution channel people interact with since birth, and no compliant rule-followers will dare to read those "filthy", "un-Christian" books. The problem of opposition will be reduced to a small cadre of intelligent and curious people who dare to question approved ideas.. they are usually the first to be lined up against the wall when totalitarian regimes come to power. At some point in the past, I would've been half joking, but this doesn't seem so unfathomable anymore.