What principle was established by the case Marbury v. Madison?

Marbury v. Madison is a landmark case in United States history that established the principle of judicial review, which is the power of the courts to examine the actions of the legislative and executive branches and determine whether those actions are consistent with the Constitution. This case arose when William Marbury petitioned the Supreme Court to compel the Secretary of State, James Madison, to deliver his commission as a justice of the peace. Chief Justice John Marshall’s decision held that while Marbury had a right to his commission, the Court did not have the authority to issue a writ of mandamus under the Judiciary Act of 1789 because that statute conflicted with the Constitution and was therefore void.

This ruling set a crucial precedent that affirmed the judiciary's role as a co-equal branch of government, possessing the authority to invalidate laws and executive actions that violate the Constitution. As a result, judicial review became a fundamental aspect of the American legal system, ensuring that the rule of law is maintained and serving as a check on the other branches of government. The establishment of this principle has had profound implications for the balance of power within the federal government and the protection of individual rights.