Which legal principle requires judges to follow precedents set by previous similar cases?

The principle that requires judges to follow precedents set by previous similar cases is known as stare decisis. This doctrine is fundamental to the common law system, as it promotes consistency and predictability in the law. When courts adhere to the decisions made in earlier cases, it ensures that similar cases are treated alike, which is essential for fairness and the rule of law.

Stare decisis facilitates the development of legal standards by providing clear guidance to judges, attorneys, and the public regarding how laws are interpreted and applied. It also allows the legal framework to evolve over time while maintaining a stable foundation upon which future cases can reliably build.

The other concepts mentioned are not related to the principle of following precedents. Res judicata deals with the issue of claim preclusion, preventing a party from re-litigating a matter that has already been judged. Actus reus and mens rea pertain to the elements of a crime: actus reus refers to the physical act, while mens rea refers to the mental state or intent behind that act. Therefore, considering their definitions, only stare decisis aligns with the requirement for judges to follow established case law.