case-by-case basis. Under the common law, judges placed great reliance on decisions in prior cases with similar facts. Although state courts today apply laws enacted by legislatures and administrative bodies, they continue the common law tradition of case-by-case interpretation of these laws and reliance on prior judicial decisions. As the United States expanded southward and westward, it acquired Mexican, Spanish, and French territories, which had legal systems based on the European civil law tradition. Under that tradition, courts in Europe applied detailed civil codes that the legislatures had designed to resolve all potential disputes. Civil codes reflected the natural law concept that there are unchanging, God-made laws that govern human behavior. Unlike in common law systems, civil law courts were not supposed to interpret the law beyond what was provided in the civil codesthey simply resolved disputes by applying the appropriate portion of the code. While the English common law tradition dominated the formation of American state legal systems, remnants of the civil law tradition exist even today, most notably in Louisiana, which based its legal system on the civil law of France. Origins of the American Judicial System: Federal Judiciary The federal judiciary was born in 1789 upon adoption of the U.S. Constitution, which vested the judicial power of the United States in "one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish." The Constitution created a judicial system that contains elements of both the common and civil law traditions. The latter is evident in one of the purposes expressed in the Constitution's preambleto "secure the Blessings of Liberty." The Constitution, however, is subject to case-by-case interpretation by the U.S. Supreme Court, which usually limits itself by the principle of stare decisis. Origins of the American Judicial System: Federalism The existence of separate federal and state judicial systems in the United States is a hallmark of federalism, which means these systems share authority to resolve legal disputes in their geographic boundaries. Federal and state courts sometimes have concurrent jurisdiction to resolve disputes arising from the same set of circumstances. For instance, federal and state authorities both took judicial action following the bombing of the Alfred P. Murrah Federal Building in Oklahoma City in 1995. Federal and state courts occasionally have exclusive jurisdiction over certain areas of the law. State courts, for instance, typically have exclusive jurisdiction to handle child custody disputes, while federal courts exclusively handle bankruptcy cases. The U.S. Constitution determines whether state and federal courts have concurrent or exclusive jurisdiction over a particular issue. Structure and Operation of the Courts: Judicial Hierarchy American state court systems are hierarchical. Most states have trial courts of general jurisdiction where the judges preside over all types of cases, both civil and criminal. Most states also have special courts of limited jurisdiction that hear only certain kinds of casesdomestic relations and family court, juvenile court, and courts for the administration of wills are typical examples. There also are state courts of inferior jurisdiction, such as justices of the peace, small claims court, and traffic