In 2008, the U.S. Fish and Wildlife Service listed the polar bear as a threatened species under the Endangered Species Act. The listing decision was controversial because it was the first time the Service had placed a thriving species on the protected list. Although sea ice habitat had been shrinking over the past 50 years, the polar bear population was expanding to an all time high of 25,000. It was also the first time the Service had listed a species based entirely on admittedly uncertain climate and population models. Finally, it was the first time the Service had listed a species while declaring that the listing would not, and could not, address the primary threat to the species–melting sea ice. We filed suit to compel the Service to explain these inconsistencies. But rather than hold the Service to account for its unprecedented listing, the trial and appellate courts deferred to the Service without requiring the agency to demonstrate that polar bears would be on the brink of extinction within the foreseeable future, as the law requires. Today, the U.S. Supreme Court declined to review the case. This effectively changes the law and sets a bad precedent for future listings. Any species with at risk habitat (i.e., virtually all species) can now be listed under the ESA, without a showing that the species itself is in decline. This will only embolden federal officials to expand their authority and lead to further abuses under the Act.