The Trump administration took another step this week to reform the implementation of the Endangered Species Act, issuing an internal memo that narrows the definition of prohibited "take" under the law.

The Sept. 14 memo, distributed to U.S. Fish and Wildlife Service field offices, states that only actions specifically intended to kill or injure an endangered animal qualify as illegal take. Accidental or incidental harm, such as a vessel striking a whale or felling a tree containing roosting bats, would no longer trigger liability unless the activity was aimed at the animal.

This reinterpretation builds on July rules that rescinded the longstanding regulatory definition of "harm," which had included habitat degradation that indirectly kills or injures species. The prior broad reading had been in place since the Reagan era and upheld by the Supreme Court in 1995. The changes took effect Sept. 14.

Interior Secretary Doug Burgum said the reforms end years of federal overreach that turned routine economic activity into regulatory traps. The administration cited the Supreme Court's 2024 Loper Bright decision as requiring agencies to follow the statute's plain text rather than expansive interpretations.

Additional July final rules eliminated the blanket 4(d) protections that automatically extended endangered-species safeguards to threatened species. Agencies must now craft tailored rules for each threatened listing. The rules also revised the critical habitat designation process to give greater weight to economic and national security impacts when deciding exclusions.

Supporters argue the updates restore the original congressional balance in the 1973 law, promote energy development and infrastructure projects, and provide greater certainty for landowners and businesses. Critics, including environmental groups and several Democratic-led states, have filed lawsuits claiming the moves weaken core protections and expose species to increased risk from development.

The Department of the Interior maintains that direct actions injuring or killing listed wildlife remain prohibited and that existing permits stay valid. The reforms align with broader administration efforts to reduce regulatory burdens while preserving the ESA's core conservation goals.