Updated

The Supreme Court appeared divided on Monday over the sole Obama administration program already in place to limit power plant and factory emissions of gases blamed for global warming.

The justices took on a small and complicated piece of the politically charged issue of cutting greenhouse gas emissions in an extended argument that included references to Dunkin' Donuts stores, football games and light bulbs. The examples were meant to illustrate the vast potential reach of the program, in its critics' view, or its limited nature, as the administration argued.

The court's liberal justices seemed comfortable with the scope of an Environmental Protection Agency permitting program that applies to companies that want to expand facilities or build new ones that would increase overall pollution. Under the program, the companies must evaluate ways to reduce the carbon they release. Carbon dioxide is the chief greenhouse gas.

However, conservative members of the bench indicated they're skeptical of the EPA's authority, with Justice Anthony Kennedy as the probable decisive vote.

One potentially narrow outcome would preserve the bulk of the program for facilities that already emit other pollutants that are regulated by the EPA.

Opponents of the program at issue concede that the case does not involve EPA's proposal of first-time national standards for new power plants or its anticipated proposed regulations for existing plants, expected this summer. It will then move on to other large stationary sources such as factories.

The case comes to the court as President Obama is stepping up his use of executive authority to act on environmental and other matters when Congress doesn't, or won't. Opponents of the EPA's program have called it a power grab of historic proportions.

Republicans have objected strenuously to the administration's decision to push ahead with the regulations after Congress failed to pass climate legislation, and after the administration of President George W. Bush resisted such steps. Both sides agree that it would have been better to deal with climate change through legislation.

Solicitor General Donald Verrilli, arguing for the administration, urged the court to leave the permitting program in place. "This is an urgent problem. Every year that passes, the problem gets worse and the problem for future generations gets worse," Verrilli said.

In 2012, a three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit concluded that the EPA was "unambiguously correct" in using existing federal law to address global warming.

Kennedy joined the court's four liberal justices in the 2007 ruling in Massachusetts v. EPA that said the agency has the authority under the Clean Air Act to limit emissions of greenhouse gases from vehicles.

Two years later, with Obama in office, the EPA concluded that the release of carbon dioxide and other heat-trapping gases endangered human health and welfare. The administration used that finding to extend its regulatory reach beyond automobiles and develop national standards for large stationary sources. Of those, electric plants are the largest source of emissions.

Chief Justice John Roberts noted that he was in dissent in the 2007 case, along with Justices Samuel Alito, Antonin Scalia and Clarence Thomas, but that the decision remains in force. The justices declined a request to reconsider that ruling as well as the core EPA decisions that underlie the permitting program.

The utility industry, the U.S. Chamber of Commerce and 13 states led by Texas are asking the court to rule that the EPA overstepped its authority by trying to regulate greenhouse gas emissions through the permitting program.

"Greenhouse gases are not included within the (permitting) program at all," said Peter Keisler, representing the American Chemistry Council among two dozen manufacturing and industry groups that want the court to throw out the rule.

In addition to environmental groups, New York, California, Illinois and a dozen other states are supporting the administration, along with the American Thoracic Society, which filed a brief detailing the health costs of climate change.

Also in support of the regulation is Calpine Corp., which operates natural gas and geothermal power plants around the nation. Calpine said it has gone through the permitting program six times and found it "neither overly burdensome nor unworkable."

Looking at the same program, the Chamber of Commerce said it "may be the costliest, most intrusive regulatory program the nation has yet seen."