On July 14, 2026, the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) published a final rule rescinding the regulatory definition of “harm,” one of nine terms listed in the Endangered Species Act (ESA)’s definition of “take.” 91 Fed. Reg. 43300 (July 14, 2026). The statute defines “take” as “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect [a protected animal or plant], or to attempt to engage in any such conduct.” 16 U.S.C. § 1532(19). Under section 9 of the ESA, a private or government entity that “take[s]” a protected species (16 U.S.C. § 1538(a)(1)(B)) is subject to citizen-based enforcement suits and civil and criminal penalties (including imprisonment). 16 U.S.C. § 1540(a), (b). Because private individuals can be sued in citizen suits irrespective of federal agency involvement (id. § 1540(g)(1)(A)), section 9 is sometimes the only predicate for ESA liability in such suits.
The rescinded regulation had defined “harm” broadly to mean “an act that actually kills or injures fish or wildlife” and includes “significant habitat modification or degradation which actually kills or injures fish or wildlife by significantly impairing essential behavioral patterns, including, breeding, spawning, rearing, migrating, feeding or sheltering.” 50 C.F.R. § 222.102 (NMFS version); see also 50 C.F.R. § 17.3 (FWS version). The agencies found that the regulatory definition was not the best reading of the statute, and therefore was no longer valid after Loper Bright v. Raimondo, in which the Supreme Court overruled Chevron deference and held that courts should uphold only statutory interpretations that reflect the best reading of a statute using the normal tools of statutory construction. Loper Bright v. Raimondo, 603 U.S. 369, 369 (2024). The agencies declined to retain any portion of the prior definition, citing a risk of confusion, and declined to promulgate a new definition, concluding the statutory definition of “take” to be sufficient.
Babbitt, Chevron Deference, and Potential Future Litigation Risks
In its 1995 decision in Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687, 699–700, the Supreme Court upheld FWS’s version of the regulation (NMFS, responsible for marine species, later adopted a similarly worded definition) from a facial challenge in a 6-3 decision. The majority’s opinion (with Justice O’Connor concurring) found the term “take” ambiguous and thus relied heavily on Chevron deference, as well as the lenient standard of review courts use when reviewing facial challenges to a statute or regulation. Justice Scalia, joined by then Chief Justice Rehnquist and Justice Thomas, wrote a lengthy dissent significantly leaning on principles of statutory construction. The final rule relies heavily on Scalia’s dissent and its underpinnings to explain the decision to rescind the prior regulatory definition. For instance, the agencies invoke the canon of noscitur a sociis (i.e., looking at the other eight examples used to define take), also cited in the Scalia dissent, to support their view that take should be interpreted “to require an affirmative act directed immediately and intentionally against a particular animal.” Id. at 726. The new preamble points out that a separate provision of the statute explicitly addresses habitat modification (section 7, 16 U.S.C. § 1536(a)(2) (requiring federal agencies to “insure that their actions do not ‘jeopardize the continued existence of any endangered species or threatened species or result in the destruction or adverse modification of habitat of such species which is determined by the Secretary, . . . to be critical.’”)), buttressing its view that FWS’s definition of “harm” to include “habitat modification” is not the “best interpretation of the statute.” See also Loughrin v. United States, 573 U.S. 351, 358 (2014) (“[W]hen ‘Congress includes particular language in one section of a statute but omits it in another’ . . . this Court ‘presume[s]’ that Congress intended a difference in meaning.”) (citations omitted).
The preamble clarifies that the change “does not limit the Services’ ability to assess impacts to listed species and critical habitats from all components of the action agency’s proposed action through the section 7 process.” It explained:
91 Fed. Reg. at 43306. Thus, the rationale for the rule also depends on the agencies’ conclusion that other provisions of the ESA, such as section 5, further ESA objectives that involve habitat replacement.
The rule states in multiple places that it does not “require that any prior permit or incidental take statement issued by the Services that relied on the prior definition of ‘harm’ be reevaluated” on the basis of the regulation. It cites a regulation (the “no surprises” rule) that specifically protects permittees in the event of changed or unforeseen circumstances. The agencies also announce plans to update their regulations concerning habitat conservation plans to ensure consistency. As for other reliance interests, the agencies generally discount them, stating that economic harms to consultants engaged in mitigation-or monitoring-related work (which the agencies cast as “a restoration and mitigation industry”) are not an appropriate consideration because such commercial enterprises, to the extent they rely on an incorrect interpretation of “take” under the ESA, are seeking prohibited “regulatory rents.” Responding to comments by state organizations that the previous congruence of their own wildlife protection laws with the regulatory definition of “harm” made it easier for them to administer these laws, the agencies reassured the commenters that federal law constitutes only the “floor.” Although the rule asserts in other places that the ESA preempts “any state law that would permit what is prohibited under the ESA or prohibit what is authorized under the ESA,” that provision of the statute expressly applies only to state laws or regulations related to “the importation or exportation of, or interstate or foreign commerce in,” threatened or endangered species. 16 U.S.C. § 1535(f).
Several organizations have filed suit and one other organization has threatened to sue. Based on previous opinions, Justice Thomas may be interested in overruling Babbitt; he believes that the overbreadth of the regulatory definition of “harm” violated the rule of lenity, among other principles. Whitman v. United States, 574 U.S. 1003, 1020 (2014) (Scalia, J. & Thomas, J., commenting on denial of certiorari) (“[I]f a law has both criminal and civil applications, the rule of lenity governs its interpretation in both settings.”). For that reason, Justices Scalia and Thomas later questioned whether the Babbitt decision should be discarded. Id. at 354 (“Babbitt’s drive-by ruling, in short, deserves little weight.”).
Nonetheless, businesses seeking permits should consider the possibility that the rule will be enjoined, at least preliminarily or in some jurisdictions, as part of their calculus.