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.