Which Supreme Court case established the principle of judicial review?

The principle of judicial review, which allows the Supreme Court to declare laws and actions of Congress or the executive branch unconstitutional, was established in the landmark case of Marbury v. Madison. This case, decided in 1803, was pivotal because it articulated the power of the judiciary to review and invalidate government actions that conflict with the Constitution.

In this case, Chief Justice John Marshall asserted that it is "emphatically the province and duty of the judicial department to say what the law is." This ruling set the precedent for the judiciary's role as a co-equal branch of government, capable of checking the powers of the other branches. As a result, Marbury v. Madison is often cited as a crucial foundational moment in the establishment of the balance of power within the United States government and underscores the courts’ authority in interpreting the Constitution.