The Judicial Branch
The Constitution says little about the judicial branch. It does not precisely spell out the power of the Supreme Court, the qualifications of Supreme Court, or even the number of justices on the Court. The Constitution does grant the judiciary the power to decide all cases that arise under the laws of the United States. In 1803, in the case of Marbury v. Madison, the Supreme Court would declare that its power and duty to interpret the law gave it the power of judicial review, the authority to declare laws that it found contrary to the Constitution were unconstitutional, and so void. The power of judicial review, although seldom used until the late nineteenth century, made the Court a much more powerful branch of government, giving greater force to the Framers' system of checks and balances.
To organize the federal judiciary, Congress passed the Judiciary Act of 1789. It created the office of Chief Justice of the Supreme Court and five associate justices (now there are eight associate justices). It also provided for an attorney general who would represent the federal government in Supreme Court cases and provide legal advice to the executive branch of government. Finally, the Judiciary Act created district courts in each of the 13 states and three circuit courts of appeal to hear disputes between citizens of of different states, as well as appeals from the district courts.
The judicial branch of government has grown very much since 1789, but it has retained its basic three-part structure: trial or district courts, appellate courts, and the Supreme Court.