The main purpose of the judicial branch of the government is to interpret and exercise the law. The Supreme Court is also charged with determining the constitutionality of all laws passed by Congress.
Congress is given the power by the United States Constitution to make laws. That power, however, restricts Congress from making any laws that fall outside of the constitutional powers granted to it. Because the Constitution is an amendable document, the founding fathers understood that it was necessary to establish a branch of government that could determine the intent of original lawmakers over time. It is also necessary for the judicial branch to determine that a law is in line with the original intent of the Constitution. The Supreme Court is atop the judicial branch of government, and it is the only court for which there is a provision in the United States Constitution. Congress is responsible for establishing smaller courts throughout the nation. Unlike most courts, the Supreme Court seldom has formal court proceedings. Instead, the justices meet to discuss the legitimacy and meaning of laws before passing down their decisions. Supreme Court justices are appointed and serve lifetime terms. There are nine Supreme Court justices, but the Constitution does not designate a specific number.