The U.S. Supreme Court is weighing whether presidential power in wartime can override environmental concerns in a case that pits the Navy's submarine-hunting training against protection for whales.

The Bush administration, in arguments Wednesday, is asking the court to undo lower court rulings that limited the use of sonar in naval training exercises off Southern California's coast.

Sonar, which the Navy relies on to locate enemy submarines, can interfere with whales' ability to navigate and communicate. There is also evidence that the technology has caused whales to strand themselves on shore.

The exercises have continued since the 9th U.S. Circuit Court of Appeals in San Francisco ruled in February that the Navy must limit sonar use when ships get close to marine mammals.

The administration says the president has the power to override federal court rulings on environmental laws during emergencies that include harm to national security. The Navy says it has already taken steps to protect beaked whales, dolphins and other creatures and is balancing war training and environmental protections.

The Natural Resources Defense Council, one of five advocacy groups that sued to force the Navy to take steps to protect the whales, argues that the Navy has to comply with environmental laws.