Judicial Review, the power of courts to review statutes and governmental actions to determine whether they conform to rules and principles laid down in constitutions. Judicial review is based on the idea that a constitution—which dictates the nature, functions, and limits of a government—is the supreme law. Consequently, any actions by a government that violate the principles of its constitution are invalid.
In the United States the most important exercise of judicial review is by the Supreme Court. The Court has used its power to invalidate hundreds of federal, state, and local laws that it found to conflict with the Constitution of the United States. The Supreme Court also has used judicial review to order federal, state, and local officials to refrain from behaving unconstitutionally. However, the power of judicial review does not belong exclusively to the Supreme Court. In appropriate cases every court in the United States may strike down laws that violate the Constitution. State courts have the power to review state government actions for compatibility with both state constitutions and the federal Constitution.
The power of judicial review is essential to the political system of checks and balances established by the U.S. Constitution, adopted in 1789. The United States would have a vastly different political system if the courts did not possess the power of judicial review. Without judicial oversight of government actions, the legislative branch would be legally supreme, and the fundamental protections included in the Constitution, such as freedom of speech, would be ineffective. The inclusion of fundamental rights in the Constitution, combined with the power of judicial review, serves to protect the minority from laws created by a slim majority because a supermajority (two-thirds of each house of Congress plus ratification by three-fourths of the states) is required to modify the Constitution...............
