Collateral Estoppel (California)
In California, the mutuality principle has been eroded and a four part test is applied to determine wheether a nonparty may rely on a prior judgment. First, the issue decided in the first case must be identical to the issue presented in subsequent case. Second, there must have been a final judgment on the merits. Third, the party against whom the judgment is to be used must have had a fair opportunity to be heard on the critical issue. Finally, the posture of the case must not be such that it would be unfair or inequitable to a party to apply collateral estoppel.