John Rawls, liberal political theorist, undertook to identify the kind of legal argument that is needed in order to secure the rule of law. In different writings, Rawls showed that the rule of law is upheld by formal legal argument, and also by ideal argument. Curiously, Rawls' affirmation of rules in the service of the rule of law, and his affirmation of ideals in the same service, came twenty years apart. Unlike Rawls, H. L. A. Hart says that ideal argument in law is not law-like in nature. Hart's view that ideals in law lack law-like qualities is a denial of law's deep duality ‒ and it is contrary to analysis of this book. Ronald Dworkin's portrait of ideal aims in law shows what fully law-like ideals look like. According to Dworkin, law's principles and policies are generally applicable directives. They state the rationales of law's rules. Like the rules themselves, they prescribe consistent disposition. Dworkin shows that ideal argument works to bring about demonstrable coherence. Law's ideal aims are organizing premises. Ideals in law are structured in relation to one another and used to structure law's rules.