The most significant result of the ruling in Marbury v. Madison was the establishment of judicial review—the power of the U.S. Supreme Court to declare acts of Congress unconstitutional.

Quick Scoop: What That Means

  • The Court announced that the Constitution is binding law that judges must follow, not just a political guideline.
  • For the first time, the Supreme Court struck down part of a federal law (the Judiciary Act of 1789) as unconstitutional.
  • This created the doctrine of judicial review, giving courts the authority to review and invalidate actions of the legislative and executive branches that conflict with the Constitution.
  • As a result, the judiciary became a truly coequal branch of government, alongside Congress and the President, within the checks‑and‑balances system.

In simple terms: Marbury v. Madison turned the Supreme Court into the ultimate referee of what the Constitution means, a role it still plays today.

TL;DR: The key result was establishing judicial review, which empowered the Supreme Court to declare laws unconstitutional and cemented the Court as a coequal branch of government.

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