What significant power did the Supreme Court establish in the early 19th century?

The Supreme Court established judicial review in the early 19th century, which is the power of the Court to examine laws and government actions and determine whether they are constitutional. This principle was solidified in the landmark case of Marbury v. Madison in 1803, where Chief Justice John Marshall asserted the role of the Supreme Court in reviewing and potentially invalidating acts of Congress that conflicted with the Constitution. This power is significant as it provides a vital check on the legislative and executive branches of government, ensuring that all actions comply with the foundational legal framework of the nation. Judicial review has since become a cornerstone of the American legal system, shaping the relationship between state and federal laws and safeguarding individual rights against government overreach.