What is the significance of Marbury v. Madison?

The case of Marbury v. Madison, decided in 1803, is significant because it established the principle of judicial review, which allows the Supreme Court to determine the constitutionality of acts of Congress and state laws. This landmark decision was the first time the Supreme Court struck down a law as unconstitutional, thereby asserting its role as a co-equal branch of government alongside the executive and legislative branches. The ruling underscored the judiciary's ability to interpret the Constitution and ensured that no law could contravene its provisions, effectively placing the Supreme Court as a critical check on legislative power. This principle has since become foundational to the American legal and political system, influencing the development of constitutional law and the balance of power between different branches of government.