Flooding the ether with bad ideas isn’t Trump’s unique know-how — it’s standard autocratic fare. Hannah Arendt used the word “preposterous” to describe the ideas that underpinned 20th-century totalitarian regimes. Bad ideas do a lot of the work of building autocracy. By forcing us to engage with them, they make our conversations, our media and our society dumber. By conjuring the unimaginable — radical changes in the geography of human relationships, the government and the world itself as we have known it — they plunge us into an anxious state in which thinking is difficult. That kind of anxiety is key to totalitarian control.