My project deals with an ancient question in political philosophy: is there any way to limit the harmful influence of misleading public speech or ‘spin’ on political decisions, especially in democracies? Recent scholars’ answers are unsatisfying: approaches that measure spin against norms of ideally reasonable speech have little practical bite, while those that merely expose its manipulations neglect the problem of citizens’ complicity in their own misleading. My study examines ancient and early modern texts that address these problems. Their strategies are philosophical and practical. They assume that people are most likely to resist misleading persuasions when they engage in self-critical reflections, and learn to judge matters of prudence and morality for themselves, not relying on others’ authority. I show that classical authors developed ingenious ways to test and train readers’ capacities for independent, self-critical judgement, and ask what we can learn from this tradition of philosophical education for citizens.