What principle did Marbury v. Madison (1803) establish?

Marbury v. Madison established the principle of judicial review by the Supreme Court, which is the power of the judiciary to review acts of the legislative and executive branches and determine their constitutionality. This landmark case laid the foundation for the role of the Supreme Court in interpreting the Constitution, ensuring that no law or executive action could violate the principles set forth in that foundational document.

This principle allows the judicial branch to check the powers of the other branches of government, reinforcing the system of checks and balances that is a cornerstone of the U.S. governmental structure. The case arose when William Marbury petitioned the Supreme Court for a writ of mandamus to compel Secretary of State James Madison to deliver his commission as a justice of the peace. Chief Justice John Marshall's ruling concluded that while Marbury had a right to his commission, the Court did not have the authority to issue the writ because the provision of the Judiciary Act of 1789 allowing for that jurisdiction was itself unconstitutional. Thus, the decision was crucial in asserting the power of the Supreme Court in shaping U.S. law and governance.