Landmark court decisions in the United States change the interpretation of existing law. Such a decision may settle the law in more than one way: establishing a significant new legal principle or concept; overturning prior precedent based on its negative effects or flaws in its reasoning; distinguishing a new principle that refines a prior principle, thus departing from prior practice without violating the rule of stare decisis; establishing a test or a measurable standard that can be applied by courts in future decisions. In the United States, landmark court decisions come most frequently from the Supreme Court. United States courts of appeals may also make such decisions, particularly if the Supreme Court chooses not to review the case or if it adopts the holding of the lower court, such as in Smith v. Collin. Although many cases from state supreme courts are significant in developing the law of that state, only a few are so revolutionary that they announce standards that many other state courts then choose to follow. Individual rights Discrimination based on race and ethnicity Dred Scott v. Sandford, People of African descent that are slaves or were slaves and subsequently freed, along with their descendants, cannot be United States citizens. Consequently, they cannot sue in federal court. Slavery cannot be prohibited in U.S. territories before they are admitted to the Union as doing so would violate the Due Process Clause of the Fifth Amendment. After the Civil War, this decision was voided by the Thirteenth and Fourteenth Amendments to the Constitution. Strauder v. West Virginia, The exclusion of individuals from juries solely because of their race is a violation of the Equal Protection Clause. This was the first time that the Supreme Court reversed a state criminal conviction due to a violation of a constitutional provision concerning criminal procedure. Yick Wo v. Hopkins, Racially discriminatory application of a racially neutral statute violates the Equal Protection Clause of the Fourteenth Amendment. Plessy v. Ferguson, Segregated facilities for blacks and whites are constitutional under the doctrine of separate but equal. As long as the separate facilities are equal in quality, then such separation is not unconstitutional. (de facto overruled by Brown v. Board of Education (1954)) Missouri ex rel. Gaines v. Canada, States with racially segregated educational systems cannot satisfy the "separate but equal" provision of Plessy merely by offering to pay for black students to be educated at