Each of the following sections will overview the origins of the current U.S. law. Exploring how past legal systems came together to constitute a uniquely American legal system.

4.6.1 Administrative Law–Agency-Made Law

State and federal legislatures cannot keep up with the task of enacting legislation on all the myriad subjects that must be regulated by law. In each branch of government, various administrative agencies exist with the authority to create administrative law. At the federal level, for example, the Environmental Protection Agency enacts regulations against environmental crimes. At the state level, the Department of Motor Vehicles enacts laws concerning drivers’ license suspension. Administrative regulations are enforceable by the courts, provided that the agency has acted within the scope of its delegated authority from the legislature.

4.6.2 Common Law

One important source of criminal law in the United States is common law. English law developed over centuries and generally, when we refer to American common law, we are referring to the common law rules brought over from England to the United States when it became a nation. It is important to note that there are no federal common law crimes. If Congress has not enacted legislation to make certain conduct criminal, that conduct cannot constitute a federal crime.

The most straightforward definition of common law is that it’s a “body of law” based on court decisions rather than codes or statutes. But what is the history of common law, and why is it so important in the United States legal System? Watch the following video on Common Law to find out.

4.6.3 Judge-Made Law: Case Law

The term case law refers to legal rules announced in opinions written by appellate judges when deciding appellate cases before them. Judicial decisions reflect the court’s interpretation of constitutions, statutes, common law, or administrative regulations. When the court interprets a statute, the statute, as well as its interpretation, controls how the law will be enforced and applied in the future. The same is true when a court interprets federal and state constitutions. When deciding cases and interpreting the law, judges are bound by precedent.

4.6.3.1 Stare Decisis and Precedent (Example)

The doctrine of stare decisis comes from a Latin phrase that states, “to stand by the decisions and not disturb settled points.” It tells the court that if the decisions in the past have held that a rule governs a certain fact situation, that rule should govern all later cases presenting the same fact situation. Stare decisis permits society to presume that bedrock principles are founded in the law rather than in the proclivities of individuals, and thereby contribute to the integrity of our constitutional system of government, both in appearance and fact” (Vasquez v. Hillery, 474 U.S. 254, 1986).

4.6.4 Court Rules of Procedure

The U.S. Supreme Court and state supreme courts make a law that regulates the procedures followed in the lower courts in the jurisdiction. These rules may provide significant rights for the defendant. For example, the rules governing speedy trials are governed by the Constitution. But the specific implementations are governed by the court rules in each jurisdiction. Local courts may also pass local court rules that govern the day-to-day practice of law in these lower courts. For example, a local court rule may dictate when and how cases will be filed in that jurisdiction.