What it actually is

Judicial review is the authority courts use to say whether a law, regulation, or government act is consistent with the Constitution. If a court finds a conflict, it can refuse to apply that law in the case before it.

This power is part of how the branches of government check each other. The Constitution creates the judicial branch, but the specific practice of judicial review developed through court decisions rather than from a single line in the text.

Both federal and state courts can consider constitutional questions. When a federal constitutional issue reaches the Supreme Court, that Court’s interpretation is the final word on the matter for the time being.

How it works

Courts don’t decide constitutional questions on their own; someone with a real legal dispute must bring a case. Judges review the law and the facts, then decide whether the challenged government action fits the Constitution.

Judges rely on the Constitution’s text, legal precedent, and rules of interpretation. A court may strike down a law, interpret it narrowly so it can stand, or allow it. Lower courts follow higher-court decisions until those decisions are changed by a higher court or by a constitutional amendment.

The Supreme Court is the final interpreter for federal constitutional questions. But its power is exercised through cases and controversies—federal courts do not issue advisory opinions or act without a concrete case before them.

A real example

In the early 1800s, the Supreme Court decided Marbury v. Madison (1803), a case that established the principle that it could review and invalidate acts of Congress that conflict with the Constitution. That decision set the pattern for later courts to weigh government actions against constitutional limits.

Since then, many cases have asked courts to apply that principle to laws and executive actions, shaping how constitutional rights and powers are enforced.

Why it matters to you

Judicial review affects everyday life because courts decide how constitutional protections apply—to speech, privacy, voting, taxes, and more. When courts interpret the Constitution, they influence what the government may and may not do.

Those rulings can change what laws mean, how agencies act, and how citizens can use or challenge government power. That’s why court cases often matter as much as legislation.

Common misunderstandings

Judicial review is not the same as making new laws. Courts interpret the law and the Constitution; elected bodies write statutes. When courts strike down laws, they are saying the law cannot stand under the Constitution as interpreted by the court.

Also, judicial review isn’t limited to the Supreme Court and it isn’t an automatic veto. Courts need a real case to act, and their rulings can be changed by later court decisions or by amending the Constitution.