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United States: Supreme Court Overturns Order Limiting Navy Sonar Training Exercises

(Nov. 21, 2008) On November 12, 2008, the United States Supreme Court reversed a lower court's order placing conditions on the U.S. Navy's training exercises using sonar, finding that the Navy's interest in conducting realistic antisubmarine training exercises outweighed the plaintiffs' interests in protecting marine mammals.

The Navy conducts exercises off the southern California coast to train for tracking enemy submarines using sonar technology. Environmentalists sued the Navy for declaratory and injunctive relief, claiming that the Navy violated federal law by failing to prepare an environmental impact statement and failing to avoid harming marine mammals. The district court initially issued a blanket preliminary injunction barring the Navy's use of sonar. The Navy appealed, and the U.S. Court of Appeals for the Ninth Circuit ordered the district court to modify its injunction to permit the Navy to conduct exercises, subject to environmental mitigation efforts. (See Court Enjoins Navy's Use of Sonar to Protect Marine Life, GLM, Dec. 2, 2007, available at // On remand, the Navy agreed to various mitigation measures, and the district court issued a modified preliminary injunction requiring further mitigation beyond what the Navy agreed to. The court's order required the Navy to shut down the sonar when a marine mammal is spotted within 2,200 yards of a vessel and to power down the sonar during a procedure known as surface ducting. The Ninth Circuit affirmed the district court's injunction, ruling that the harm to marine mammals from the training exercises was significant and that the district court's conditions on the Navy's exercises were unlikely to adversely affect the exercises.

The Supreme Court reversed the Ninth Circuit, ruling that a preliminary injunction was inappropriate in this case. Noting that a preliminary injunction requires a court to find, among other things, that the balance of competing claims of interests and harms favors plaintiffs, the Court ruled that the plaintiffs' ecological, scientific, and recreational interests in preventing harm to marine mammals are outweighed by the interest of the Navy in conducting effective antisubmarine training exercises. The Court relied on declarations in the record from senior Navy officers warning of significant burdens on the conduct of training exercises from the injunction's conditions, and found that the lower courts understated these burdens.

The majority opinion by Chief Justice Roberts was joined by four Justices. Two Justices concurred in part and dissented in part, while two Justices dissented. (Winter v. Natural Resources Defense Council, Inc., No. 07-1239 (Nov. 12, 2008), available at