The duty of the judicial branch is to interpret the laws. Or, in the words of Chief Justice John Marshall, “to say what the law is.” Article III has been interpreted by the Supreme Court to give the judiciary the power to declare acts of the president or Congress unconstitutional. This power, known as judicial review, gives American courts much more influence than in other countries.

Article III is the shortest, and least specific, of the constitutional provisions establishing the three branches of government. The framers of the Constitution spent far less time—and debate—on the judiciary than Congress or the president. Yet the power of unelected judges to overturn laws in a democracy has become one of the most controversial issues in American government.