Judge Friedman of the District of Columbia District Court today vacated the Service's 2007 rule designating the Western Great Lakes distinct population segment of wolves and delisting the same. The court held that the ESA is ambiguous as to whether the Service has the power to reconstitute an existing listed species as several DPSs, and then delist one or more of those DPSs. The court remanded the matter to the Service to give it the opportunity to articulate why the Service's position is a reasonable construction of the ESA which would merit deference under Chevron. Although Judge Friedman's statutory interpretation is not especially remarkable, his Chevron analysis is, for it supposes that the Service's interpretation of the ESA that is set forth in a particular delisting decision is eligible for Chevron deference. It would be, to say the least, unusual for an agency interpretation of a statute that purports to apply to just one statutory "instance" (as it were) to merit Chevron deference. This issue is currently being litigated in the Ninth Circuit in Arizona Cattle Growers' Association v. Kempthorne, a case concerning a challenge to the critical habitat designation for the Mexican spotted owl. There, the district court held that the Service's interpretation of the ESA's critical habitat provisions is eligible for Chevron deference, even though the interpretations apply only to the owl's habitat and to no other.