A more thorough explanation:

Definition: A horse case, also known as a whitehorse case, is a reported legal case that has facts that are almost identical to the current case. The outcome of the reported case can be used to determine the outcome of the current case.

Example: In a case where a person was injured in a car accident due to a faulty brake system, a previous case with similar facts where the court ruled in favor of the injured party can be used as a horse case to argue for a similar outcome in the current case.

The use of horse cases is common in legal arguments as it helps lawyers to establish a precedent for their case. By using a horse case, lawyers can show that a similar situation has been previously ruled on and use that ruling to support their argument.