A federal court sitting in diversity must apply the issue preclusion law of the state where it sits, so California issue preclusion law will apply to these Plaintiffs.

Federal courts sitting in diversity must apply the forum state's law in determining the preclusive effect of a prior judgment.

Because the Court is sitting in diversity, it applies the substantive law of the forum state, Alaska, including the collateral estoppel rules of that state

The party asserting collateral estoppel "has the burden of showing that the issue was actually adjudicated in a prior proceeding."

We also review de novo the district court's application of collateral estoppel to the issue of paralegal fees.

Because this is a diversity action, state law controls whether the previous state court determinations have a preclusive effect on Plaintiff's claims.

—addressing Washington products liability statute barring "a product liability claim where the product has passed its `useful safe life'"and presuming that time period to be at least 12 years (quoting Wash. Rev. Code § 7.72. 060