[JURIST] The US Supreme Court [official website; JURIST news archive] ruled [opinion, PDF] 6-3 Wednesday in Winter v. National Resources Defense Council [Cornell LII backgrounder; JURIST report] that the US Navy may continue using sonar as part of military training exercises, despite environmentalists' concerns for the impact this has on whales and other marine life. Chief Justice John Roberts wrote for the majority:

We do not discount the importance of plaintiffs’ ecological, scientific, and recreational interests in marine mammals. Those interests, however, are plainly outweighed by the Navy’s need to conduct realistic training exercises to ensure that it is able to neutralize the threat posed by enemy submarines.

Justice Stephen Breyer filed an opinion concurring in part and dissenting in part, in which Justice John Paul Stevens joined as to Part I. Justice Ruth Bader Ginsburg filed a dissenting opinion, in which Justice David Souter joined. Ginsburg wrote:

In light of the likely, substantial harm to the environment, [National Resource Defense Council’s] almost inevitable success on the merits of its claim that [the National Environmental Policy Act] required the Navy to prepare an [Environmental Impact Statement], the history of this litigation, and the public interest, I cannot agree that the mitigation measures the District Court imposed signal an abuse of discretion.

The decision overturns a ruling [opinion, PDF] by the US Court of Appeals for the Ninth Circuit that upheld a preliminary injunction against the Navy. AFP has more. SCOTUSblog has additional coverage.