Arguments before the Supreme Court and a lower court on Tuesday will put two pillars of President Obama's first-term air-quality agenda on trial.
The Supreme Court will hear arguments over the Environmental Protection Agency's 2011 Cross-State Air Pollution Rule. It requires states in the eastern half of the U.S. to cut smog- and soot-forming pollution from power plants that blows across state lines.
An appeals court knocked down the rule in 2012, but the EPA asked the high court to review the case.
Not far away, the U.S. Court of Appeals for the D.C. Circuit will hear challenges from industry groups and several states to a separate EPA rule that requires cuts in power-plant emissions of mercury and other toxic compounds.
The stakes are high.
"I think that killer coal-fired power plants are literally on trial," said Frank O'Donnell of the advocacy group Clean Air Watch. "What's at stake is the health of many millions of Americans who for years have been subject to disease and sickness from coal-fired power plants."
The twin events will focus on detailed legal questions, but the court cases are part of a much wider battle over energy policy and coal.
The arguments will help decide the fate of a White House environmental agenda that industry groups and many Republicans call overzealous and economically harmful, especially in coal-producing regions and areas heavily reliant on coal for power.
"They have been much more aggressive than any prior administration in using the Clean Air Act and in particular using the Clean Air Act to go after coal-fired power plants," said Jeffrey Holmstead, now a partner at Bracewell & Giuliani, a firm that counts power companies among its clients.
Holmstead, who was EPA's top air quality official under President George W. Bush, said the mercury and air-toxics rule before the appeals court is the costliest in EPA history.
The agency estimates the regulations will have nearly $10 billion in annual costs. However, EPA estimates that the health benefits of the rules far outweigh the costs.
The groups attacking and defending the rules in the courts mirror parties waging intense political and lobbying battles over the White House agenda — struggles that are intensifying as EPA crafts separate second-term rules to curb carbon emissions that affect climate change.
Groups challenging the air-toxics standards before the appeals court include utilities with coal-fired plants, the National Mining Association, and a number of states including Texas.
At the Supreme Court, meanwhile, the EPA and its allies will ask the justices to breathe life into the cross-state rule that the D.C. Circuit struck down last year. The appeals court, in a 2-1 decision, said the EPA took an overly expansive view of its power to force emission cuts under the Clean Air Act's "good neighbor" provision. The provision enables the EPA to require pollution cuts in states that "contribute significantly" to the failure to meet air quality standards in areas downwind. But the judges said the EPA rule goes well beyond that threshold.
"EPA has used the good neighbor provision to impose massive emissions reduction requirements on upwind States without regard to the limits imposed by the statutory text," the 2012 ruling stated.
The high court will also explore whether EPA ran roughshod over states by requiring compliance with "federal implementation plans" to meet the requirements without first giving states the chance to make pollution cuts.
EPA estimates that the Obama administration's cross-state rule, when phased in, would prevent 34,000 premature deaths, 15,000 nonfatal heart attacks, 19,000 cases of acute bronchitis, and 400,000 cases of aggravated asthma annually.
The 2012 appeals-court decision ordered EPA to continue implementing a less-strict Bush-era version of the rule.
Justice Samuel Alito has recused himself in the Supreme Court case.