Enacted law is the entire body of law that a government has implemented, including its constitution, the legislation that’s been passed by the legislature and signed into law by the executive, and the regulations promulgated by government agencies to carry out the legislation. It differs from common law, often called case law, which is enunciated by the country’s judicial system in the course of applying and interpreting enacted law. Enacted law often lays the bare framework of the law, while the common law fills that framework.
The American judicial system is based on the British system, which was in effect in the American colonies until the American Revolution. The British system employed a concept of common law, in which the courts would establish legal principles based on the legislation enacted by Parliament. In many cases, it was the courts, and not the Parliament, that established criminal law. Once the American system was up and running, though, the Supreme Court declared that that particular feature of the common law system wouldn’t continue in the United States, thus reinforcing the idea that the legislature, and not the courts, was the supreme authority in creating law.
Changing enacted law through legislative action is often difficult to accomplish, due both to the workload of the legislature and political pressures. When changes are made, they're often radical simply because of the length of time since the last revision. The judicial system, largely immune to political pressure, interprets and clarifies the law on almost a daily basis, often accommodating changes in technology and society. In general, changes to the law accomplished through the judiciary are gradual, but from time to time can be dramatic. It also needs to be understood that the courts are bound fairly strictly by precedent, so new cases are adjudicated in light of the way prior cases were handled.
A famous example of a sudden and dramatic change in both enacted and common law was the end of state-ordered segregation in public schools. Segregation in public schools was common in the United States; indeed, it was a core component of many states’ law, and the system was upheld in an 1896 ruling of the Supreme Court on the grounds that “separate but equal” educational facilities did not violate the Constitution. Thus, the enacted law of many states, affirmed by the common law, was that segregation was legal. When the issue was raised again in 1956, in Brown v Board of Education, the Court overturned its earlier ruling, stating that “separate education facilities are inherently unequal.” By changing the common law, Brown also overturned enacted law in all the states where legal segregation prevailed.
Had the American system required legislative action to accomplish that objective, it might well have taken decades, especially considering the charged political atmosphere of the time. Yet without a single vote cast in any legislature, one of the fundamental elements of American law was overturned, literally overnight. The court’s decision in Brown was controversial, though, and its opponents had viable remedies available to counter it; none was ever seriously attempted, though.
The relationship of enacted law and the common law in contracts and torts is also complex. Torts — causes of action that have no criminal component — are rooted in British common law, and thus survive in the American system, often by reference in legislated law. Some causes of action, though, such as wrongful death, did not exist in the British common law and have only been established in some American jurisdictions by legislative action. A lawsuit for wrongful death cannot be brought in a jurisdiction that does not have a wrongful death statute; by contrast, negligence has long been a cause of action under the common law, and no special statute is necessary to bring an action for negligence.
Enacted and common law in the United States, then, exist in a complex relationship with each other. The enacted law, the product of elected officials, is superior to the common law, yet the common law often gives clarification to that law, and in some cases can overturn it. In addition, elemental concepts of the law may sometimes be more appropriately declared by the judiciary in expressions of the common law, than may be expected from the legislature,