The states are bound by the decisions of the Supreme Court and cannot choose to ignore them. Decided September 12, 1958 (argued September 11, 1958). Opinion of the Court: Charles Evans Whittaker → go there Applied: the Fourteenth Amendment → go there Topic: Federalism. Cooper v. Aaron, 358 U.S. 1 (1958), is a landmark decision of the Supreme Court of the United States that denied the school board of Little Rock, Arkansas the right to delay racial desegregation for 30 months. On September 12, 1958, the Warren Court delivered a decision that held that the states are bound by the Court's decisions and must enforce them even if the states disagree with them, asserting the judicial supremacy established in Marbury v. Madison (1803). The decision in this case upheld the rulings in Brown v. Board of Education and Brown II which held that the doctrine of separate but equal was unconstitutional. Wiki link