Collateral estoppel, or issue preclusion, precludes a party from relitigating in a subsequent action or proceeding an issue that was clearly raised in a prior action or proceeding and decided against that party or those in privity. The doctrine gives conclusive effect to prior determinations when two conditions are met: (1) there must be an identity of issue which has necessarily been decided in the prior action and is decisive of the present action, and (2) there must have been a full and fair opportunity to contest the decision now said to be controlling. The determination of whether a party had a full and fair opportunity to litigate in the prior proceeding requires a practical inquiry into the realities of the prior litigation. The burden of proof is on the proponent to establish the duplicative identity of the party against whom the doctrine is sought to be applied and the issues of the two proceedings, but the party seeking to avoid application of the doctrine has the ultimate burden of establishing the absence of a full and fair opportunity to have litigated the earlier matter.
Lennon v. 56th & Park (NY) Owner, LLC, NY Slip Op 04972 (2d Dep't September 15, 2021)
