Final answer:
Judicial review, while not expressly stated in the Constitution, is a fundamental aspect of the American legal system established by the Supreme Court in Marbury v. Madison. It empowers courts to invalidate laws conflicting with the Constitution, thereby serving as the "linchpin of the Constitution" due to its central role in maintaining checks and balances.
Step-by-step explanation:
Judicial Review: The Linchpin of the Constitution
The term judicial review refers to the power of the courts to analyze the constitutionality of actions taken by the other branches of government and by the states. It is a cornerstone of the American legal system and often cited as a critical mechanism for upholding the checks and balances embodied in the Constitution. Although not explicitly mentioned in the Constitution, the concept of judicial review was anticipated by figures such as Alexander Hamilton and was formally established in the landmark case of Marbury v. Madison in 1803. This case set the precedent for the court's ability to declare legislative acts invalid if they are found to be in conflict with the Constitution.
Despite its overarching importance, judicial review has been exercised with restraint. Throughout its history, the Supreme Court has used this power sparingly, invalidating a relatively small percentage of the total number of laws passed by Congress. Still, judicial review remains a potent and essential function of the judiciary, ensuring that no law or executive action violates the supreme law of the land. This foundational role justifies why many consider judicial review as the "linchpin of the Constitution".