Industry groups and Republican-led states are heading an attack at the Supreme Court against the Obama administration's sole means of trying to limit power-plant and factory emissions of gases blamed for global warming.

As President Barack Obama pledges to act on environmental and other matters when Congress doesn't, or won't, opponents of regulating carbon dioxide and other heat-trapping gases cast the rule as a power grab of historic proportions.

The court is hearing arguments Monday about a small but important piece of the Environmental Protection Agency's plans to cut the emissions — a requirement that companies expanding industrial facilities or building new ones that would increase overall pollution must also evaluate ways to reduce the carbon they release.

Environmental groups and even some of their opponents say that whatever the court decides, EPA still will be able to move forward with broader plans to set emission standards for greenhouse gases for new and existing power plants.