Winter v. Natural Resources Defense Council, Inc.

Background

The Navy planned 14 integrated antisubmarine training exercises off southern California using mid-frequency active sonar. Environmental groups and individuals, including the Natural Resources Defense Council and Jean-Michel Cousteau, sued saying sonar harms marine mammals and that the Navy should have prepared a full environmental impact statement before the exercises. A District Court enjoined sonar use and imposed six mitigation measures. The Ninth Circuit narrowed the relief but affirmed two contested limits: a 2,200‑yard shutdown zone and a power-down during surface ducting.

Reasoning

The Court focused on whether a preliminary injunction was justified. It held plaintiffs must show irreparable harm is likely, not merely possible, and that courts must weigh the balance of harms and public interest. The Court gave substantial deference to senior Navy officers about realistic training needs, concluded the injunction’s challenged measures would seriously harm antisubmarine readiness, and therefore vacated those parts of the injunction. The Court did not finally decide the underlying NEPA merits.

Real world impact

As a practical result, the Navy may continue mission-critical sonar training while it completes an environmental impact statement. The President and the Council on Environmental Quality had already authorized alternative arrangements and a coastal exemption, but the Court’s priority was preventing interruption of readiness. Because the EIS remains pending, environmental rules could still change future training practices.

Dissents or concurrances

Justice Breyer would have kept modified interim conditions in place until the EIS was finished. Justice Ginsburg dissented, arguing the District Court reasonably balanced harms and that CEQ lacked authority to bypass NEPA.