Democracy is the ongoing product of public discussion. 1 With what legitimacy, then, can a democracy limit its citizens' participation in that discussion? The question has crystallised in recent years around problems of "extreme" expression, 2 with a particular focus on so-called "hate speech." 3 Extreme expression plays a paradoxical role in a democracy. On the one hand, it involves a small fraction of all messages. Even democracies passionately combatting it tend to bring few prosecutions and to impose mild penalties. Stronger crackdowns generally target high-profile provocateurs like Jean-Marie