[T]he “rights” conception [of the rule of law] assumes that citizens have moral rights and duties with respect to one another, and political rights against the state as a whole. It insists that these moral and political rights be recognized in positive law, so that they may be enforced upon the demand of individual citizens through courts or other judicial institutions of the familiar type, so far as this is practicable. The rule of law on this conception is the ideal of rule by an accurate public conception of individual rights. It does not distinguish, as the rule-book conception does, between the rule of law and substantive justice; on the contrary it requires, as part of the ideal of law, that the rules in the rule book capture and enforce moral rights.