Administration and auto industry lawyers say the high court should dismiss the states' lawsuit. They argue that the nation's global warming policy is a political issue to be decided by Congress and the president, not a legal issue to be decided in court.
This argument may well appeal to Chief Justice John G. Roberts Jr., who has said the court should adopt a more modest role and allow politicians to set policies.
But environmental activists and the state lawyers were pleasantly surprised in June when the Supreme Court voted to take up the case, Massachusetts vs. EPA, despite the objections of the Bush administration.
If the court rules squarely on the question of whether the Clean Air Act regulates greenhouse gases, the stakes will be high for environmentalists, California's regulators and the auto industry.
"If we win, it will free California and other states from a legal threat," said Bookbinder, the Sierra Club lawyer. "But if the Supreme Court says the Clean Air Act does not cover climate change, it would be hard for California to say it has the authority to regulate greenhouse gases."
If the court rejects the Bush administration's stand, the automakers will be under pressure to produce vehicles that get better gas mileage.
The court could also issue a split decision.
It could rule that carbon dioxide is an air pollutant under the Clean Air Act, but that the EPA's administrator is free to decide whether to issue new emissions standards for it. In the past, the court has been very reluctant to require an agency to issue new regulations.
A split decision would not force the federal agency to regulate greenhouse gases, but it could clear the way for California and the states to do so on their own.
Besides Massachusetts and California, the states challenging the Bush administration's policy are Connecticut, Illinois, Maine, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont and Washington.
They were joined by the cities of New York, Washington and Baltimore, and several environmental groups.
david.savage@latimes.com
