The U.S. Constitution divides the federal government into three branches. The judicial branch, headed by the Supreme Court , decides cases under the nation's laws. The other two branches are the legislative branch , called Congress, and the executive branch , headed by the president of the United States.
Most of the Constitution's provisions concerning the judicial branch appear in Article III, which begins, “The judicial power of the United States, shall be vested in one Supreme Court, and in such inferior courts as the Congress may from time to time ordain and establish.” The Constitution does not list any qualifications that a person must meet in order to be a judge.
Judicial power is the power to decide cases that arise under the U.S. Constitution, federal laws, and treaties with foreign nations. It also covers other kinds of cases, such as those affecting ambassadors, public ministers, and consuls; cases involving the seas; cases in which the United States is a party; and cases between different states or between citizens of different states.
The Constitution distinguishes between original jurisdiction and appellate jurisdiction. Original jurisdiction is the power to hold a trial to make a first decision in a case. The Supreme Court's original jurisdiction power only covers cases in which a state is a party, and cases affecting ambassadors, public ministers, and consuls. In all other cases, the Supreme Court has only appellate jurisdiction, which is the power to review decisions from lower courts for errors.
The Constitution says that Congress may create courts inferior to the Supreme Court. Congress has divided the United States into twelve circuits, eleven of them numbered and one covering the District of Columbia. These circuits each have one circuit court of appeals and many district courts. The district courts, which hold trials, are scattered throughout the states in federal districts. The circuit courts of appeals hear appeals from the district courts. Parties who lose in the circuit courts of appeals may ask the Supreme Court to review the case.
The Constitution says that trials for all crimes must be heard by juries, and must be held in the same state in which the crime was committed. No person may be convicted of the crime of treason except by confession in court, or by evidence that includes testimony from at least two persons concerning the specific act of treason.