By Paul Weiland and Svend Brandt-Erichsen (November 28, 2018, 5:34 PM EST) -- On Nov. 27, 2018, in an 8-0 decision in a case argued before Justice Brett Kavanaugh's confirmation, the U.S. Supreme Court ruled in Weyerhaeuser Co. v. U.S. Fish and Wildlife Service that an area is eligible to be designated as "critical habitat" under the Endangered Species Act, or ESA, only if the area is habitat for the relevant threatened or endangered species.[1] The court vacated the Fifth Circuit's earlier decision in the case, which held that the ESA has no habitability requirement, and remanded the case to the Fifth Circuit to interpret the term "habitat," which is not defined in the ESA.  Additionally, the court held that a decision by the U.S. Fish and Wildlife Service not to exclude an area from designated "critical habitat" is subject to judicial review. These two holdings are likely to limit the service's expansive interpretation of its authorities and provide the regulated community with the ability to challenge designation of areas as critical habitat where such action has adverse economic consequences....