This paper explores the connections between two central topics in moral and political philosophy: the moral legitimacy of authority and the ethics of causing harm. Each of these has been extensively discussed in isolation, but relatively little work has considered the implications of certain views about authority for theories of permissible harming, and vice versa. As I aim to show, reflection on the relationship between these two topics reveals that certain common views about, respectively, the justification of harm and the moral limits of authority require revision. The paper defends two main claims. The first considers the normative situation of agents who are commanded to inflict serious harm on others. Under what conditions (if any) ar...