In Hight v. Hight (1977) 67 Cal.App.3d 498, the wife filed an action in Colorado to recover arrearages and current support under the Colorado version of Revised Uniform Reciprocal Enforcement of Support Act of 1968 (RURESA), and the Colorado court certified the complaint stated a cause of action and forwarded the matter to the District Attorney of Humboldt County, where the husband resided. Husband appeared at the hearing and argued (as an affirmative defense) wife had frustrated his visitation rights, and the Humboldt County District Attorney appeared but wife did not. The court's order denied relief and, in a subsequent action for arrearages, husband asserted the prior order was res judicata. Although the Hight court invoked Greenfield to deny res judicata effect to the prior judgment, res judicata could have been rejected on the ground that an essential element (e.g., the parties to the prior judgment were the same or substantially identical) was absent. Hight specifically noted wife had only a "nominal status as a party" to the first proceeding (Hight, at p. 504), and that it was the district attorney in California who was in actual control of the proceeding. (Ibid.)