Also referred to as mandatory precedent, binding precedent is an existing law to which a court is expected to adhere. All inferior or lower courts are expected to follow the laws of a superior court in a particular jurisdiction.
Under the United States legal system, courts take a certain hierarchy. The Supreme Court is the highest court of the land, while the lower federal courts fall underneath it. The Supreme Court is given the ultimate authority by the U.S. Constitution on all questions about the federal law, and states in the U.S. abide by a common law system. This allows the existence of a binding precedent due to common law jurisdictions.