Attorney General Phil Weiser joins 16 state AGs opposing Trump administration proposal to weaken Endangered Species Act

May 19, 2025 (DENVER) — Attorney General Phil Weiser is joining a coalition of 16 attorneys general in sending a comment letter to the Trump administration opposing a proposed rule by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service to rescind the regulatory definitions of “harm” under the federal Endangered Species Act, or ESA.

This change, if finalized, would significantly weaken the law’s ability to protect wildlife, especially from habitat threats, including damage to breeding and feeding grounds and polluting or draining critical water sources, even if those actions lead to the death or injury of protected ESA-listed species.

“Colorado has a long history of people from all backgrounds working together to protect our wildlife while ensuring economic progress and development. This latest action by the Trump administration to weaken federal protections threatens dozens of species,” said Attorney General Weiser. “Our state’s ecosystems are complex and fragile, and any attempts to throw our system of defending and protecting endangered species out of balance could have devastating unforeseen consequences. I will continue to fight for our land, air, water, and wildlife.”

Enacted by Congress in 1973 with bipartisan support, the ESA provides a national program for protecting endangered and threatened species and their habitats. Since then, the ESA has helped bring back several species from near-extinction, including the U.S. national bird, the bald eagle. In Colorado, federally protected species include the black-footed ferret, ​the whooping crane, and the Colorado pikeminnow, among others (opens new window).

In their letter, the attorneys general argue that the proposed rule, if finalized, will significantly reduce protections for vulnerable species and make it much harder to save such species from extinction, which is contrary to the plain language and purposes of the ESA, as well as longstanding Supreme Court precedent and other case law upholding the existing definitions. The attorneys general also argue the proposed rule violates the Administrative Procedure Act and the National Environmental Policy Act.

Read a copy of the comment letter (PDF).

Attorney General Weiser is joined in submitting the comment letter by the attorneys general of Arizona, California, Connecticut, Illinois, Maryland, Massachusetts, Maine, Minnesota, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington.

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Media Contact:
Elliot Goldbaum
Community Education & Communications Manager
(720) 508-6769 office
elliot.goldbaum@coag.gov