"It is emphatically the province and duty of the judicial department to say what the law is," stated Chief Justice John Marshall in a unanimous opinion in the 1803 Supreme Court case of Marbury v. Madison. This landmark case established the doctrine of judicial review, which gives the court the authority to declare executive actions and laws invalid if they conflict with the U.S. Constitution. The court's ruling on the constitutionality of a law is nearly final-it can only be overcome, by a constitutional amendment or by a new ruling of the court. Through the power of judicial review, the court shapes the development of law, assures individual rights, and maintains the Constitution as a "living" document by applying its broad provisions to complex new situations.