Trump Administration Issues Significant Final Revisions to Endangered Species Act Regulations

On July 17, 2026, the U.S. Fish and Wildlife Service (FWS) issued a final significant set of revisions to regulations implementing the Endangered Species Act (ESA), continuing the Trump Administration’s broader effort to reshape federal environmental regulation through a combination of deregulation, statutory reinterpretation, and reliance on the Supreme Court’s decision in Loper Bright Enterprises v. Raimondo. The latest rulemaking follows several ESA actions proposed in late 2025 that sought to restore much of the regulatory framework adopted during the first Trump Administration after many of those provisions had been revised by the Biden Administration in 2024. Together, these actions represent potentially one of the most consequential shifts in ESA implementation in years and illustrate how agencies are increasingly reevaluating longstanding regulations in light of the Supreme Court’s rejection of Chevron deference.

The July 17, 2026, final rule addresses two important components of ESA implementation. First, FWS eliminated the “blanket Section 4(d) rule” for threatened species. Section 4(d) of the ESA authorizes FWS to issue regulations it considers “necessary and advisable” for the conservation of threatened species. Under regulations reinstated by the Biden Administration in 2024, newly listed threatened species generally received protections similar to those afforded endangered species unless FWS adopted species-specific exceptions.

The new rule reverses that approach. Rather than automatically extending endangered-species protections, FWS will instead develop tailored, species-specific Section 4(d) rules where appropriate. According to the Administration, this approach more closely follows the statutory distinction Congress created between “endangered” and “threatened” species and allows the agency to calibrate regulatory protections based on the needs of individual species. Congress intentionally distinguished “threatened” from “endangered.” The new interpretation argues that if Congress wanted threatened species automatically treated like endangered species, it would have written the statute that way. Section 4(d) gives the Secretary of the Interior discretion, not a mandate, to determine what protections are “necessary and advisable” for each threatened species.

Second, the rule revises the process for excluding areas from critical habitat designations. Section 4(b)(2) requires FWS to consider economic impacts, national security impacts, and other relevant factors when designating critical habitat. The revised regulations restore a framework similar to one adopted during the first Trump Administration that provides greater discretion to exclude areas from critical habitat where the benefits of exclusion outweigh the benefits of designation, provided that doing so would not result in the extinction of the species. “Benefits of exclusion” is really a balancing test. The agency weighs benefits of designation against benefits of exclusion and may exclude only if: (1) exclusion benefits outweigh designation benefits; and (2) exclusion will not cause extinction. The Administration argues that these revisions provide greater transparency and predictability for landowners, project developers, and regulated entities.

These revisions follow another notable ESA action finalized just one week earlier. On July 10, 2026, FWS and the National Marine Fisheries Service (NMFS) rescinded the long-standing regulatory definition of “harm” under the ESA. For decades, agency regulations interpreted “harm” to include significant habitat modification that actually kills or injures protected wildlife. FWS and NMFS concluded that interpretation exceeded the statutory text and cited Loper Bright as requiring agencies to adopt what they view as the “single best meaning” of the statute rather than relying on broader policy-based interpretations. One notable feature of the final rule is that its justification rests heavily on statutory interpretation rather than the type of policy or scientific analysis often associated with environmental rulemakings. The agencies repeatedly invoke Loper Bright and Justice Antonin Scalia’s dissent in Babbitt v. Sweet Home Chapter, Communities for a Great Oregon to argue that the prior regulatory definition exceeded the statutory text. Whether that legal rationale alone satisfies the Administrative Procedure Act’s requirement for reasoned decision making will likely become a central issue in the inevitable litigation challenging the rule.

Although the agencies emphasized that the ESA’s prohibitions on directly injuring or killing listed species remain unchanged, the removal of the habitat-based definition of “harm” is likely going to have substantial implications for future permitting decisions, enforcement actions, and litigation involving habitat modification.

Viewed together, these rulemakings reflect more than isolated regulatory amendments, they demonstrate a broader change in how federal agencies are approaching environmental statutes. Throughout 2025 and 2026, the Administration has undertaken a government-wide review of environmental regulations, in line with President Trump’s Executive Order 14192, “Unleashing Prosperity Through Deregulation,” frequently emphasizing:

• Adherence to statutory text;

• Reduced regulatory burdens;

• Greater certainty for regulated entities;

• Expanded consideration of economic impacts; and

• Reliance on the Supreme Court’s decision in Loper Bright as justification for revisiting prior agency interpretations.

The ESA revisions are among the clearest examples of this philosophy. Rather than expanding agency discretion to address conservation objectives through broad regulatory interpretations, the new rules seek to — or argue that — agencies should anchor implementation more closely to what the agencies characterize as the plain language enacted by Congress.

The regulatory changes are almost certain to generate litigation. Environmental organizations are expected to challenge several aspects of the new regulations, particularly the rescission of the habitat-based definition of “harm” and the elimination of the blanket Section 4(d) protections. Future litigation will likely test not only whether the agencies have properly interpreted the ESA, but also how courts apply Loper Bright when reviewing competing statutory interpretations.

For regulated industries, including infrastructure developers, manufacturers, agriculture, forestry, mining, and energy producers, the revisions may provide greater regulatory flexibility and predictability in certain permitting and consultation processes. At the same time, the prospect of extended litigation means that regulated entities will face uncertainty for an extended period of time and will need to continue to monitor developments closely before assuming that the new regulatory framework will remain unchanged, a response becoming increasingly common following the administration change from Trump to Biden to Trump again.

The ESA has long occupied a central role in environmental policy because it sits at the intersection of conservation, land use, infrastructure development, and federal permitting. These latest revisions demonstrate that debates surrounding the statute are increasingly becoming debates about administrative law itself. As agencies continue reevaluating longstanding regulations following Loper Bright, the ESA may serve as an early indicator of how other environmental programs, including those administered under the Clean Water Act, Clean Air Act, and other federal environmental statutes, could evolve in the coming years.