20 States and DC Sue Over ESA 'Harm' Redefinition in 2 Lawsuits

For attorneys and regulatory compliance teams, this case is a major test of administrative rulemaking on the Endangered Species Act. The central dispute—whether habitat degradation falls within the statute's definition of 'harm'—will hinge on statutory interpretation, likely under Administrative Procedure Act standards, and could set durable precedent for how agencies define protective scope across environmental statutes.

The legal fight over the U.S. Endangered Species Act escalated sharply on September 9, 2026, when Democratic attorneys general from 20 states and Washington, D.C., filed two coordinated lawsuits against the Trump administration, alleging that newly issued federal rules illegally weaken the landmark 1973 conservation law. The lawsuits, announced just under two months after the Department of the Interior and the Department of Commerce finalized the rules, target three specific regulatory changes: a narrowed definition of "harm" under the ESA, elimination of default protections for newly threatened species, and a requirement that business objections and economic burdens be considered before critical habitat is designated. In a statement quoted by Reuters, Washington Attorney General Nick Brown described the changes as "a reversal of staggering proportions" and said the administration's approach to land and water "is one of exploitation."

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The rules were finalized less than two months before the suits, and the litigation is part of a wider pattern of Democratic state attorneys general challenging Trump administration environmental rollbacks in court.

The Endangered Species Act, enacted by Congress in 1973, is one of the most consequential U.S. environmental statutes. It has been credited with saving species such as the California condor, the grizzly bear, and the humpback whale, and with protecting the bald eagle from habitat loss driven by development. The litigation now centers on how broadly the statute obligates federal agencies and private actors to avoid harming those species and their habitats. The first lawsuit challenges a rule that narrows the ESA's definition of "harm," which states say had long included encroachments on habitats where endangered animals live. Under the new rule, oil drilling, mining, and other activities may proceed in those habitats so long as they are not "directed immediately and intentionally" against particular animals, even if they cause injuries or death. The second lawsuit targets two additional rules: one removes broad protections for newly threatened species unless the U.S. Fish and Wildlife Service issues species-specific protections, and another requires the government to weigh business objections, including potential economic burdens, before designating "critical habitats."

For industry, the stakes are substantial. Developers, fossil fuel companies, and mining interests would face fewer federal obstacles under the new rules, particularly in areas that environmental advocates argue are essential for species survival. But the legal challenge introduces significant uncertainty. Companies planning projects in or near sensitive habitats may need to prepare for potential delays, injunctions, or additional state-level scrutiny even as the rules are litigated. The fact that the plaintiffs represent 20 states plus Washington, D.C., signals broad Democratic opposition and suggests the case will proceed through coordinated multi-state litigation, likely before federal district courts and potentially on appeal. The states contend that the administration overstepped statutory authority and contradicted congressional intent—a claim that will likely turn on judicial interpretation of the ESA's text and prior agency practice.