A judicial decision that changes or has a substantial effect on an existing law is known as a what?

A judicial decision that changes or has a substantial effect on an existing law is referred to as a landmark decision. Landmark decisions are significant because they set precedents that can influence future legal interpretations and decisions. These rulings often address major legal principles or constitutional issues, leading to notable changes in the law or legal interpretation.

For instance, landmark decisions can redefine rights, shape legal standards, or clarify legal concepts that are critical to the justice system. They are often cited in future cases as authoritative examples of how a particular legal issue has been resolved, reflecting their lasting impact on the law.

Understanding the concept of landmark decisions is essential for those studying law and policy, as these cases illustrate the evolving nature of the legal system and its responsiveness to societal changes.