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 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.