Common law is the body of law that has evolved out of judicial (court) decisions rather than being enacted by legislatures. It is also called case law. It developed in England and came to America with the colonists. All states except Louisiana, which follows the Napoleonic Code inherited from French settlers, follow the English system.^[1]

Common law is based on the concept of precedence, which requires judges to decide a dispute based on previous decisions in cases with similar facts. Not all previous cases are precedents. A judge has to consider court hierarchy, case relevance, and jurisdiction. As summarized by the Indiana Court System, “When a decision is made by a higher court, the lower courts must follow it. Once a case is decided, it establishes a precedent, or a judicial decision that should be followed when a similar case comes to court. To serve as precedent for a pending case, a prior decision must have almost the same question of law and almost the same facts. If the precedent is from another area, such as another state’s Supreme Court, it can be considered, but it does not have to be followed.” In this way, new decisions can become a legal precedent. A binding precedent is referred to by the Latin phrase stare decisis or “let the decision stand.”