Undoubtedly, to be of use, most rules or systems of rules require a method of enforcement, whether the method be remedial in nature, such as a civil judgment, or a penal sanction imposed in a criminal matter. John Austin, a proponent of the social fact thesis of legal positivism, contends that the primary distinguishing feature of a legal system is whether its rules can be enforced (1995). Austin argues that a rule of law in society is legally valid if and only if that rule is commanded by the society's sovereign and is backed up with the threat of sanction, or enforcement (1995). As such, it is Austin's position that the essential element of a law is whether someone has the ability to sanction its noncompliance.
Austin's position seems tenable. Indeed, without enforcement, laws have no effect. To ensure compliance, and in the absence of any moral obligation to obey a law, an absence which we must presume, a law must impose a consequence for a violation. Even the rules that govern the application of law, such as rules of procedure, require some sort of sanction for a breach. A prominent philosopher of law, H.L.A. Hart, has suggested that Austin's position on enforcement is clear when applied to those laws that restrict our behavior, but is inapplicable to the set of rules that grant us the power to create rights and obligations, such as contracts and wills (1994). Even those rules, however, are "enforced" through sanction, to wit, the threat of litigation and the possibility of voiding, for example, a created document should it contain a flaw.
And the essence of such litigation, indeed the very root of its existence, is that law is subject to interpretation. Ronald Dworkin, a pillar of modern legal philosophy, believes that adjudication is and should be interpretive (1982). According to Dworkin, judges should look to the "political structure of their community" when deciding hard cases by, first, ensuring that their interpretation is in accordance with the community's existing legal practices, and, second, that the interpretation is presented in the best moral light (1982). As such, Dworkin posits that a law is specifically characterized by its language, the facts to which the law must be applied, and the best moral application of that law given the social practices of a particular community.
The idea that law is a set of rules subject to interpretation was also recognized by the legal realist movement. Inspired by John Chipman Gray and Oliver Wendall Holmes, and reaching its analytical peak in the 1920s and 1930s, legal realism contradicted legal formalism by asserting that judicial decision making is guided far more frequently by the political and moral insights of the judge rather than by legal rules (Himma, 2006). Legal formalism embraced the concept that a judge's decision, or holding, would always logically follow from the legal rule being applied to a particular set of facts, leaving little or no room for interpretation (Himma, 2006). The realist model asserts the opposite extreme, claiming that (1) any matters worth litigating are thereby divisive enough to require interpretation of the applicable rules, (2) judges make new law in exercising discretion when deciding legal disputes, and (3) when deciding