WASHINGTON - Whales may simply have to pay the price as the Navy prepares for war, Supreme Court justices suggested Wednesday.

In a closely watched environmental case, justices Wednesday morning repeatedly sounded sympathetic to Pentagon officials who want to run large-scale Navy exercises off the Southern California coast. While the resulting underwater sonar storm disturbs marine mammals, it also helps prepare sailors for combat.

"I thought the whole point of the armed forces was to hurt the environment," Justice Stephen Breyer said, half-jokingly. "Of course they're going to do harm."

The Pentagon and environmentalists disagree over exactly how much mid-frequency active sonar injures marine mammals, and justices Wednesday couldn't resolve the conflict. An apparent majority of justices, though, did appear ready to defer to military expertise in matters of national security.

Justices wrestle with the issues

Chief Justice John Roberts raised the specter of an undetected "North Korean diesel submarine to get [closer] to Pearl Harbor" if sailors couldn't train with sonar, and Justice Samuel Alito asked pointedly if a judge could be considered "an expert on anti-submarine warfare." Alito added that there is "something incredibly odd" about a trial judge making a decision "contrary" to the Navy's requirements.

Even Breyer, who at times has been skeptical about other claims of executive authority, suggested that "an admiral [who] comes along with an affidavit that seems plausible" might outrank a "district judge who just says" the training should stop.

"You're asking us [for a decision], who know little about whales and less about the Navy," Breyer told Los Angeles-based attorney Richard Kendall, who is representing environmental groups.

The technical but crucial legal question in Winter vs. Natural Resources Defense Council is when a federal agency can sidestep conventional environmental protections by declaring an emergency. A Pentagon victory could make such emergency declarations more common, and on more than just military matters.

Even before the hourlong oral arguments Wednesday, legal scholars were predicting the conservative-led court was likely to defer to military necessity in time of war. The prediction is enhanced by the fact that Winter vs. Natural Resources Defense Council arises from the San Francisco-based Ninth Circuit Court of Appeals, which the Supreme Court reversed in eight out of 10 cases last year.

Case pits whales against sailors

It's the conflict between whales and sailors, though, that gives the case its sizzle.

Underscoring the stakes -- and perhaps as part of a bit of courtroom staging -- an array of uniformed Navy officers sat in the front row of the visitors section Wednesday.

The Navy uses the Southern California Operating Area for training exercises, which prepare naval strike groups for deployment to the Pacific Ocean and Middle East. Sailors use mid-frequency active sonar to detect otherwise hard-to-find submarines.

The Southern California coastal waters are also home to at least 37 species of marine mammals, including pygmy sperm whales, coastal bottlenose dolphins and endangered blue whales.

The Navy's sonar produces piercing underwater sounds that Kendall said was 2,000 times louder than a jet engine. Some scientists say sonar use can cause hearing loss, cranial bleeding, behavioral modifications and mass strandings in whales.