Law, simply put, is the formal pronouncement of the rules which guide our actions. Legislatures, state and federal, make laws. So do local governments. Executive branches and agencies implement laws through regulations. Courts enforce and interpret laws and regulations and settle disputes through their decisions.
The output of these law making bodies goes into print and online resources. The material produced by these groups becomes much of what is in law libraries and what lawyers consult during their legal research. The collection of materials are referred to by specific terminology:
Outline of the U.S. Legal System, Bureau of International Information Programs, United States Department of State (PDF)
So how does someone find the relevant law? How do you identify specific documents in these reporters and codes? First, keep in mind there is a great difference between retrieving a known document and researching or trying to find documents that help you answer a legal question. If you have a citation to a specific legal document like a statute or a court decision it is fairly easy to retrieve that specific document. [See the Citations tab.] Conducting actual legal research is much more complex. The legal publishing world has created a number of research aids:
Precedent is based on stare decisis, which means “to stand on what has been decided". The principle developed in English common law and establishes that the decision of a court not only settles a dispute between the parties involved but also sets a precedent or model to be followed in future, similar cases. The idea is that we all benefit by the consistency of courts interpreting the same statute in the same way.
A decision is binding authority (also called mandatory or controlling) on the court that issued the decision and on lower courts in the same jurisdiction for the disposition of factually similar controversies. In a hierarchical system like our state and federal court systems, the decision of a trial court can bind future decisions of that trial court, but the decisions do not bind other trial courts or appellate courts. Appellate courts can bind themselves and lower courts over which they have appellate jurisdiction, but appellate courts cannot bind each other by their decisions.
Another important principle in our legal system is that of jurisdiction.
Jurisdiction is power, the power or authority of the court to decide a matter in controversy. The authority to compel witnesses to testify or command people to turn over documents or property, or to jail them for contempt. Jurisdiction is established in constitutions and by statute and is usually done geographically or by subject.
There are some matters over which a state or federal court has exclusive jurisdiction and some matters over which a state court has concurrent jurisdiction with the federal courts. Federal courts can, in some instances, decide questions of state law; state courts can, in some instances, decide questions of federal law. Sometimes it might be difficult to determine which matters are questions of federal, or state law, or both.
The final concept is the court structure. In general, there are trial courts and appellate courts.
When a case is appealed to an appellate court, both parties submit written briefs that contain a summary of the facts and arguments on the points of law involved, and the court may hear oral arguments by the attorneys. The court then issues an opinion which states the legal basis for the decision.
If the case is decided by an intermediate appellate court, the losing party may be able to appeal one more time. This second appeal is usually at the discretion of the higher court.