The Supreme Court's rebuke Monday of President Bush's policy on global warming appropriately rejected the administration's absurd argument that it doesn't have the authority to regulate greenhouse emissions.
But the real impact of the high court's unexpectedly strong stand in support of carbon dioxide curbs to combat global warming will likely be in Congress, where lawmakers now have a powerful case for federal action. And affected industries should be newly motivated to cooperate, if only to avoid a patchwork of state legislation.
Among the state anti-pollution efforts that benefited from the court ruling was the General Assembly's "clean cars" proposal that would require automakers to cut fleetwide emissions of smog pollutants and global warming gases from cars sold in Maryland by 30 percent as of 2016.
Local car dealers were hoping carbon dioxide would be stricken from the list of regulated emissions through a legal challenge brought against a similar statute in California. But the Supreme Court's ruling this week makes such an outcome unlikely.
Under the Bush administration, the Environmental Protection Agency has refused to use its authority from the Clean Air Act to regulate carbon dioxide on the grounds that it is not a contributor to dirty air but a naturally occurring gas produced in part by respiration. A majority of the court, though, found scientific evidence persuasive that carbon dioxide produced in large quantities by the burning of fossil fuels and trapped in the atmosphere results in a harmful warming effect - posing the sort of threat Congress had in mind when the Clean Air law was enacted.
In a separate decision, the court unanimously upheld the EPA's authority to require power plants that expand their facilities to increase pollution curbs on smokestack emissions. The ruling is important in Maryland in part because it overturned a pro-industry decision by the 4th U.S. Circuit Court of Appeals, which hears cases from this region.
With this affirmation of regulatory authority, the stage should be set for aggressive action by the executive branch. But (no surprise here) Mr. Bush made clear yesterday that he's still in no hurry. So Congress must move forward on its own with tough standards for motor vehicles as well as smokestacks.
Global warming is already having harmful effects - including melting polar ice caps, rising seas and extended droughts. The urgency of remedial action can hardly be overstated. The United States has been dragging its heels for too long.