Climate change and invasive species are jeopardizing already endangered and threatened species, prompting the U.S. Fish and Wildlife Service (FWS) to finalize its 2023 rule allowing experimental populations to be introduced into habitat outside their historical range, as long as the areas are capable of supporting the experimental population. This Comments argues the determination that the ecosystem is already “capable of supporting” the species should satisfy Weyerhaeuser habitat requirements, that FWS' regulatory change is necessary to further the conservation of the species in light of existing and imminent threats to endangered species and their habitats posed by climate change or invasive species, and that judges should defer to the environmental agencies, which base their determinations on “the best scientific and commercial data available.”