By Lawrence Hurley
WASHINGTON (Reuters) - The Supreme Court appeared closely divided on Monday over whether the administration of President Barack Obama exceeded its authority in trying to regulate greenhouse gas emissions.
Justice Anthony Kennedy would seem to hold the swing vote on the nine-member high court, with conservative justices skeptical of the U.S. Environmental Protection Agency's approach and liberal justices generally supportive.
During a 90-minute oral argument, Kennedy offered some criticism of the government's position but did not indicate which way he would vote.
In his most outspoken question, Kennedy clashed with the Obama administration's lawyer, Solicitor General Donald Verrilli, over some of the government's legal arguments.
"I can't find a single precedent that strongly supports your position," Kennedy said.
The justices are weighing just one aspect of the administration's first wave of climate change regulations, focusing on whether the agency has authority under the Clean Air Act to regulate greenhouse gases under a program for stationary sources of pollution, such as power plants and oil refineries.
The court has various options if it finds fault with the government's conclusion that greenhouse gases should be regulated under the "prevention of serious deterioration," or PSD, program, which requires any new or modified major polluting facility to obtain a permit before any new construction is done if it emits "any air pollutant." The program requires facilities to install the best available technology to control emissions of specific pollutants.
One option discussed by the justices would require facilities already subject to the permit program for other air pollutants to be regulated for greenhouse gases but would exempt other facilities. Alternatively, the court could exempt all facilities from the program in relation to greenhouse gases.
The ruling is unlikely to have a broad impact on the administration's climate strategy, including plans to introduce greenhouse gas standards for new power plants under a separate provision of the Clean Air Act. The standards were announced in September but have yet to be formally issued.
Questions posed by the justices made it clear the court is highly unlike to revisit a landmark 2007 case, Massachusetts v. EPA, when it held on a 5-4 vote that carbon was a pollutant that could potentially be regulated under the air pollution law.
A decision is expected by the end of June.
(Additional reporting by Valerie Volcovici; Editing by Howard Goller, Grant McCool and Douglas Royalty)