Judith Shklar’s negative brand of liberalism is sometimes thought to have little to say about the ethical character required of citizens in liberal democracies, beyond the injunction to avoid cruelty. In this article, however, we argue that Shklar’s negative liberalism prescribes four distinctively political virtues—rational empathy, a healthy apprehension of state power, self-restraining tolerance, and being a good loser—that, taken together, constitute an ethos of skeptical vigilance. We survey Shklar’s criticisms of republican and communitarian accounts of civic virtue to clarify her concerns about attempts by the liberal state to cultivate these virtues and analyze the case of passive injustice to highlight tensions between active citizenship and liberal values. We conclude with some reflections on how Shklar’s political theory attempts to persuade her readers of the importance of adopting and practicing an ethos of skeptical vigilance.