Review this quote from the decision in Marbury v. Madison.

It is emphatically the province and duty of the Judicial Department to say what the law is.

How does this excerpt summarize the case?

Answer:It explains that the Supreme Court should decide whether a law or action is constitutional.

This excerpt is the core of the doctrine of Judicial review.

Marbury v. Madison enabled the Judicial branch to become a co-equal branch of Government through the holding of the power to review legislative and executive branch action to determine whether it was constitutional. This excerpt establishes that quite clearly.