Landmark decision A Landmark decision, or Landmark court decision, establishes new precedents that establish a significant new legal principle or concept. Or it changes the interpretation of existing law. In Commonwealth countries, a reported decision is said to be a leading decision. This is when it has come to be generally regarded as settling the law of the question involved.[1] A landmark decision is "a most important case which has establish a law firmly in an area, usually referring to a U.S. Supreme Court case."[2] A landmark decision may have either long-term or short-term significance.[3] Politics, economics or other changes in society may reduce the effects of a landmark decision. A landmark decision is one that changes an entire area of the law during a period of time.[4] The United States Constitution did not provide for judicial review of laws and court decisions. It was a power the US Supreme court assumed (took) for itself with its first landmark decision.[3] In the decision Marbury v. Madison (1803) the court established its "power to say what the law is".

Abstract The nature of American constitutional politics was forever changed during the Progressive Era. In the nineteenth century, the process of constitutional interpretation was a vague and decentralized enterprise balanced between the courts and the public square. The meaning of the Constitution was decided as much at the polls or on the battlefield as in court opinions. This balance started to give way at the turn of the century as federal courts began asserting greater authority in the definition of constitutional bounds. “Bench over Ballot” illustrates how the assertion of judicial supremacy in the Progressive Era precipitated a fight that upended the traditional dynamic of American politics. Populist-progressives championed the people's ultimate right to correct judicial decisions while traditionalist-conservatives stood for judicial supremacy to ensure a “government of laws.” The outcome of the political battle in 1912 was a consensus between Wilsonian progressives and Taftian conservatives in favor of judicial supremacy that banished the notion of popular supremacy and transformed the nature of constitutional politics from a popular, decentralized process to a vicious battle over the personal composition of the bench—a phenomenon deeply familiar over a century later.