What is essential for a matter to apply for issue preclusion?

For issue preclusion to apply, it is essential that the issue in question must have had a valid, final judgment in an earlier case. This is because issue preclusion, also known as collateral estoppel, prevents the same issue from being relitigated once it has been decided in a prior action. The requirement for a valid and final judgment ensures that the determination made in that earlier case was not only conclusive, but it also had a definitive resolution, allowing the parties to rely on that judgment in subsequent litigation.

If this condition is not met, the essence of issue preclusion fails, as there would be no established legal principle to apply to the current case. This principle promotes judicial efficiency by preventing parties from repeatedly arguing settled issues and upholding the integrity of prior judicial decisions.

In this context, it's important to note that the involvement of the same parties or issues being discussed in different contexts does not, by themselves, meet the necessary criteria for issue preclusion. Additionally, resolutions through mediation do not typically result in a valid final judgment that can trigger issue preclusion since such resolutions often lack the formal judicial determination required for enforcement.