On September 14, 2026, a final rule from the U.S. Fish and Wildlife Service and the National Marine Fisheries Service took effect rescinding the regulatory definition of “harm” under the Endangered Species Act. Since the 1970s, that definition had included “significant habitat modification or degradation which actually kills or injures fish or wildlife by significantly impairing essential behavioral patterns.” The Supreme Court upheld it in 1995. The agencies, citing the Court's 2024 decision ending deference to agency interpretations, removed it.
Interior Secretary Doug Burgum said, “For years, federal agencies abused the ESA to obstruct lawful land use and burden American families and businesses.” The Interior Department said, “Actions that directly injure or kill listed wildlife will continue to be prohibited.” The change narrows what counts as illegally harming a protected species when the harm comes through destroying its habitat. Two companion rules, which changed how critical habitat is designated and ended blanket protections for newly listed threatened species, took effect August 20.
Twenty states and Washington, D.C., sued on September 9, calling the changes “a reversal of staggering proportions,” and environmental groups and tribes have filed separate suits. Rep. Brian Fitzpatrick (R-PA), the House bill's lead Republican sponsor, said, “when habitat destruction actually kills or injures protected wildlife, that destruction is harm.” Sens. Adam Schiff and Sheldon Whitehouse introduced a resolution to overturn the rule. Former Fish and Wildlife Service Director Daniel Ashe said, “All of us agree that this is a stake through the heart of endangered species conservation.” An Interior spokesperson said the states' lawsuit “seeks to preserve a decades-old regulatory overreach.” Beyond Fitzpatrick, congressional opposition so far has come from Democrats.