Courts often are called upon to review cases in which there is a dispute as to whether a law or a government official's action is permitted under the Constitution. The Supreme Court has the final word in such cases. For this reason, the Court is a major factor in the balance of power among the three branches of government established by the Constitution. Under the power of judicial review, for example, the Court may rule on the legality of a town's zoning law, a lower court's conduct of a trial, a school board regulation, or an action by a policeman or the president of the United States.

This power is not provided for directly in the Constitution. The Court itself defined it in 1803 in the case Marbury V. Madison. Chief Justice John Marshall wrote the opinion. It declared that judicial review is the outgrowth of English and American legal traditions along with certain provisions of the Constitution itself. The reasoning was that courts first must decide what laws mean in order to rule on cases arising under them; that the Supreme Court must decide the meaning of the Constitution in order to defend it as the "supreme law of the land"; and, finally, it must decide whether a law or action is in agreement with the Constitution, because it may recognize only laws which are made in pursuance of that basic law, according to Article VI, Paragraph 2. If the Court finds that a law or action is not in agreement with the Constitution, it can declare it unconstitutional and unenforceable.

In order to carry out its functions, Congress must gather information. Such functions include passing laws on a vast variety of subjects, approving treaties, evaluating individuals nominated by the president, and appropriating money for carrying out the programs of government. Closely associated with this is the authority to require individuals to appear and provide necessary information—the subpoena power.

Although the investigating power is not specifically provided for in the Constitution, it has been considered part of our lawmaking tradition from the earlier state legislatures and the English Parliament. It is a significant power in the check and balance system. There are limits to it, however. The Supreme Court has said that the Congress may not investigate to restrict the First Amendment rights of individuals or to attempt to exercise powers assigned to the executive and judicial departments.

The Constitution says nothing about the size of the Supreme Court or whether it can be changed from time to time. Under Article III, Section 1, Congress established the judicial system in the Judiciary Act of 1789. It established a six-member court. At various times since, the size has been changed to seven, ten, and the present nine members. The Court has made no ruling on the subject.

Background for the notes has been obtained from Edward S. Corwin, and Jack W. Peltason, Understanding the Constitution (New York: Holt, Rinehart, & Winston, 1964).