Supremes to decide whether EPA can or must regulate greenhouse-gas emissions

Tomorrow, the U.S. Supreme Court will begin hearing arguments in Massachusetts v. EPA, a humdinger of a case looking at whether the federal government can or must regulate greenhouse-gas emissions. The case centers on a Clean Air Act provision that requires regulation of air pollutants that “may reasonably be anticipated to endanger public health or welfare.” The plaintiffs (a cadre of 12 states, three cities, and green groups) argue that planet-toasting greenhouse gases fit that description. The Bush administration, on the other hand, claims that GHGs are not air pollutants, and thus that the U.S. EPA doesn’t have the authority to regulate them. And you know how squeamish the White House gets about overstepping the bounds of lawful executive authority. The Bush squad also contends that even if they can regulate GHGs, that doesn’t mean they must. (And furthermore, they never asked to be born!) While all eyes will be on tomorrow’s action, a ruling isn’t expected until next summer.