By a vote of 8–0 (Justice Kavanaugh did not participate), the Supreme Court today gave a rational reading of both the Endangered Species Act (ESA) and its own power to review administrative agency actions. The decision in Weyerhaeuser v. U.S. Fish & Wildlife Service is an important win for property owners against arbitrary agency decisions. See Cato’s amicus brief here.

The case arose when the Fish and Wildlife Service (FWS), which administers the ESA on behalf of the Secretary of the Interior, designated a large parcel of land in Louisiana owned by Weyerhaeuser and a group of family landowners as critical habitat for the endangered dusky gopher frog, a small population of which lives today in Mississippi. The problem, however, was that the frog had not lived in Louisiana for decades and, worse still, the land in question, far from being critical habitat, was no habitat at all since it was unsuitable for sustaining the frog’s life cycles. On appeal, FWS did not dispute that critical habitat must be habitat; it argued instead that habitat includes areas that would require “some degree of modification” to support a sustainable population of a given species. In her dissent from the Fifth Circuit’s decision, Judge Priscilla Owen nicely summarized the immense practical implications of that view: “If the Endangered Species Act permitted the actions taken by the Government in this case, then vast portions of the United States would be designated as ‘critical habitat’ because it is theoretically possible, even if not probable, that land could be modified to sustain the introduction or reintroduction of an endangered species.”

Fortunately, Chief Justice Roberts, writing for the Court, today carefully parsed the ESA’s language to avoid that result. And of equal if not greater importance, he did the same to sustain the Administrative Procedure Act’s “basic presumption of judicial review” of agency action, finding here that the ESA requires the Secretary to take into consideration economic and other impacts before making a critical habitat designation. The economic impact to these plaintiffs of losing their right to develop their land was estimated to be $34 million—all to preserve a frog’s uninhabitable habitat. No wonder the decision was 8–0. Still, the plaintiffs had to go all the way to the Supreme Court to vindicate their rights.

The Court sent the case back to the Fifth Circuit to be resolved consistent with today’s opinion.