To better understand the role and function of law one must understand both the federal court and state court structures. The federal court structure is a three-part configuration; the top court is the United States Supreme Court, which is the top court in the federal judicial system.
Additionally, many refer to the Supreme Courts as "the highest court in the land", because it has the definitive authority to consider appeals in virtually all cases ruled upon in the federal court system. The Supreme Court can also sit in judgment of certain appeals from each state’s Supreme Courts. These involve a federal inquiry, for instance, a dispute encompassing a federal statute or on involving the Constitution of the United States. Additionally, the Supreme Court maintains a restricted “original jurisdiction” over certain cases. Even so, less than 100 cases are essentially listened to and ruled on by the Supreme Court during a given year ("Appellate Court", 2015).
The second part of the three-part structure is the Federal Courts of Appeal. The Federal Courts of Appeal are separated into twelve distinctive regions including the District of Columbia circuit, more commonly identified as circuit courts ("Structure of the Federal Courts", n. d. ). These circuit courts are only appellate courts and hold no “original jurisdiction” (Melvin, 2011). The third part of this structure is the Federal District Courts. “The Federal District Courts are the trial courts of the federal court system” (" Structure of the Federal Courts," n. d. ).
Contained by boundaries that are set by the Constitution through Congress; additionally the circuit courts retain jurisdiction to try almost every category of federal cases, as well as criminal and civil issues.