It's a shame that Shamu and Flipper weren't available to offer their thoughts to the Supreme Court Wednesday, as the justices were presented with starkly conflicting views over the impact of sonar technology on marine life.

The U.S. Navy says its use of mid-range frequency sonar during training exercises has minimal impact on whales and dolphins. The Natural Resources Defense Council, which successfully blocked the Navy from using the sonar, says it causes great harm.

NRDC attorney Richard Kendall was quite dramatic when he likened the sound of the underwater sonar to the noise that would be created by 2,000 jet engines roaring in the courtroom.

Kendall described the specific impact on beaked whales, who try to surface when hit with the sonar waves. "[S]ince they dive down for so long, if they come up too fast they get the bends," he told the Court. "When they do the necropsies of these beaked whales, they find hemorrhaging, the embolisms in various parts of the bloodstream and many, many deaths."

The Navy says 40 years of successful sonar testing in the Pacific Ocean shows sonar technology is relatively harmless. Justice Samuel Alito pressed the Navy's lawyer on this point, that any harm to marine life was most likely to be temporary and without injury. This harm was described as whales and dolphins simply turning away from the sonar or brief disruptions to their feeding or breeding patterns.

Wednesday's arguments mark the high-water mark of many years of litigation and disputes between the environmentalist group and the Navy's Third Fleet, based in San Diego. The rather basic practical dispute rests on the harm the sonar waves pose to marine mammals. The two sides were unable to reach agreement on how far from a sonar testing ship mammals like whales and dolphins had to be for them to be safe.

This failure to reach an accord drew some exasperated comments from Justice Stephen Breyer: "[W]hy couldn't you work this thing out?" Breyer went on to wonder why "you are asking us who know nothing about whales and less about the military to start reading all these documents to try to figure out who's right in the case where the other side says the other side is totally unreasonable."

The other significant issue for the Navy is its assertion that the training exercises are essential for sailors who will need the skills in hostile waters. "The ability to locate and track an enemy submarine through the use of mid-frequency active sonar is vitally important to the survival of our naval strike groups deployed around the world and therefore critical to the nation's own security," said newly installed Solicitor General Gregory Garre, representing the Navy.

In response to Justice Breyer's somewhat flippant point that all military actions leave an environmental impact, NRDC lawyer Kendall said, "I think the point of the armed forces is to safeguard our freedoms causing the least damage possible to our environment."

There are also technical and procedural issues at play that may be the basis for a ruling that could come later this year. The technical issue is the significance of the Navy's failure to timely complete an Environmental Impact Statement as prescribed by law. Instead, they conducted a different — and what critics decry as a less critical — analysis to determine its sonar testing was not harmful. A ruling could rest on the need to acquire the EIS before conducting the sonar tests. The Navy says its EIS will be completed in January, thus raising issues of what significance any decision will have relative to the specifics of this case.

The procedural issue is the amount of deference the district court judge gave the Navy before issuing an injunction that effectively put the Navy's sonar tests in dry-dock. Several justices expressed concern that Judge Florence Marie Cooper failed to sufficiently consider the Navy's concerns.

Justice Alito seemed particularly bothered by this circumstance. "Isn't there something incredibly odd about a single district judge making a determination on that defense question that is contrary to the determination that the Navy has made?" he asked.