They also hear cases where people are charged with federal crimes, such as bank robbery. There are three levels of federal courts.
District courts are the lowest.
Next are courts of appeals. If people involved in a case don't agree with the rulings of lower courts, they can appeal to the highest court in the land - the U.S. Supreme Court. But the supreme court only hears cases the 9 justices believe are important and might settle unresolved legal issues in the United States. Sometimes, ordinary criminal cases spark rulings that change the whole legal system. In 1965, Miranda v. Arizona, the Supreme Court ruled a man's conviction had to be thrown out because police did not tell him he had the right to a lawyer when arrested.