Discussions of legal ethics generally assume that lawyers should deliberate straightforwardly on the basis of reasons to act or refrain from acting. This model of deliberation fails to account for the role of the law in resolving normative disagreement and coordinating social activity by people who do not share comprehensive ethical doctrines. The law represents a collective decision about what citizens ought to do, which replaces the reasons individuals would otherwise have to act. This Article contends that legal ethics ought to be understood as an aspect of this theory of the authority of law. On this account, lawyers have a duty not to reintroduce contested moral beliefs into the law by relying on them as a justification for action with...