Nine justices, appointed for life by the President, with the "advice and consent" of the Senate, interpret and apply the Constitution and all federal statutes, usually after decision by federal courts of appeals and state supreme courts. The Supreme Court hears argument in about 170 cases each year. If you lose your case in the federal court of appeals (or, sometime, in the state supreme court as here in New Hampshire), you can ask the Supreme Court to hear your appeal. However, unlike a court of appeals, the Supreme Court doesn't have to hear it. In fact, the Supreme Court hears only a small number of the cases it is asked to take.