The basis for the Supreme Court’s power of judicial review is that it is an implied power derived from the structure and text of the U.S. Constitution, interpreted to mean that federal courts (including the Supreme Court) have the authority to interpret the Constitution and declare laws or government actions unconstitutional when they conflict with the Constitution. This principle was established by Marbury v. Madison (1803), where Chief Justice John Marshall stated that it is the duty of the Judicial Department to say what the law is and that courts must decide whether acts of Congress or the other branches conflict with the Constitution. Although the Constitution does not explicitly grant a standalone “judicial review” power, the combination of Article III (jurisdiction over cases arising under the Constitution) and the Supremacy Clause (the Constitution is the supreme law of the land) has been interpreted to confer this ultimate policing authority on the judiciary. The Court’s role as the ultimate arbiter of constitutional validity is reinforced by long- standing practice and numerous subsequent cases that have applied and refined the scope of judicial review, while respecting the separation of powers doctrine. Key points to understand:

• Implied power: Judicial review is not expressly stated in the Constitution; it was inferred from constitutional text and the judiciary’s role in interpreting laws.
• Marbury v. Madison: Established the framework for review, asserting the judiciary’s duty to say what the law is and to strike down laws or executive actions that are unconstitutional.
• Supremacy and Article III: The Constitution’s supremacy and the federal judiciary’s expressed jurisdiction to interpret the Constitution underpin the power to invalidate conflicting federal or state actions.
• Separation of powers: Courts exercise review without creating policy; they interpret and declare legality, preserving the legislative and executive roles in lawmaking and administration.

If you’d like, I can provide a concise quote from Marbury v. Madison and map how Article III and the Supremacy Clause interact to justify judicial review, along with a short timeline of landmark cases that expanded or clarified the doctrine.