The Supreme Court is made up of nine judges, called justices, who are nominated by the President and confirmed by the Senate. One of these justices, called the chief justice, heads the court. A Supreme Court justice serves until he or she dies or resigns (quits in the middle of his or her term). When that happens, the president nominates someone new to replace the justice who left. If the Senate agrees with that choice, the person becomes a justice. If the Senate does not agree with the president's choice, then the president must nominate someone else.