While the Navy was staging war games and hunting down "enemy" submarines with sonar off the island of Kauai two summers ago, more than 150 lost and disoriented whales were swimming chaotically in the shallows of Hanalei Bay.
That mass stranding was a scene neither the Navy nor environmentalists want to see repeated as 40 ships from eight countries return to the islands this month for the world's largest international maritime war games.
But the two sides agree on little else, including whether sonar was to blame for that incident.
The continuing dispute highlights a deep divide over how to best protect marine mammals while safeguarding the nation's defenses.
This week, environmentalists won a temporary restraining order to stop the Navy from using a high-intensity sonar during this year's Rim of the Pacific 2006 exercise, which had scheduled sonar use to start Thursday.
The federal judge's order Monday came just days after the Defense Department granted the Navy a six-month exemption from certain federal laws protecting marine species to allow use of the "mid-frequency active sonar." Environmentalists had argued that the exemption was aimed at circumventing their lawsuit.
The Navy's failure to take a "hard look" at the environmental impact of war games was an "arbitrary and capricious" violation of the National Environmental Policy Act, U.S. District Judge Florence-Marie Cooper wrote in granting the restraining order.
Government lawyers were reviewing the ruling and the Navy will probably respond soon, said Jon Yoshishige, a spokesman for the U.S. Pacific Fleet in Hawaii, reports AP.