The plan is now frozen because last February, the Supreme Court voted to delay implementation until the appeals process could play out.
The nation's second most powerful court spent almost seven hours Tuesday trying to decide whether President Obama's signature plan to fight global warming represents a transformative environmental initiative or tramples on the prerogatives of Congress and the states.
Attorneys representing the state opposition seemed to find more traction arguing that the EPA was playing fast and loose with the Clean Air Act in order to find a way to regulate greenhouse gas emissions without an act of Congress.
President Barack Obama's plan for shifting US electrical power generation away from coal and toward cleaner sources was labeled in court as an illegal power grab that would force the creation of a "new energy economy".
"The collective coalition was able to put very strong legal arguments forward as to why this regulation is unlawful and why it should be set aside", West Virginia Attorney General Patrick Morrisey said at a Tuesday evening press conference. "Melting ice caps and glaciers are causing sea levels to rise at alarming rates, threatening shorelines here in ME and around the world".
"This was a good day in court for America's Clean Power Plan and for healthier air, a safer climate and economic prosperity", she said. Angus King and former U.S. Sen.
Supporters, including 19 states, several scientific and conservation groups, and some electric utilities, say the CPP is a reasonable way to reduce pollution and help the country meet its global pledge to avoid unsafe levels of warming in the future.
"This is a huge case".
"That's the point of the clear statement doctrine", Lin said.
The Appeals Court respected the fact that the EPA was first and foremost doing its bit to tackle the intractable and ever-evolving issue of climate change by addressing head on the largest source of air pollution.
"Why isn't this debate going on right now on the floor of the Senate, rather than before a panel of unelected judges?" asked Judge Thomas Griffith, another Bush nominee.
Judge Brett Kavanaugh, a Republican appointee, suggested other EPA rules and many states have used trading programs successfully.
But West Virginia Solicitor General Elbert Lin, also speaking at Georgetown, said he thought that the court understood that the Clean Power Plan is different than other regulations authorized by the Clean Air Act.
The clean-energy train has already left the station in the form of affordable renewable energy already making major carbon pollution reductions today.
The law compels the agency to devise the "best system of emission reductions" (BSER) for any given pollutant, EPA lawyers noted, and that's what the agency did after the Supreme Court ruled in 2007 (Massachusetts v. EPA) that the EPA must regulate carbon under the act. Unless Congress steps in, Kavanaugh said, "Lots of people are going to lose their jobs, lose their livelihoods".
The U.S. Court of Appeals for the District of Columbia Circuit is scheduled to hear oral arguments on the Clean Power Plan, which aims to slow climate change by reducing power-plant emissions by one-third.
Power plants are the largest source of USA carbon emissions.
He argued that Congress indeed may have meant to prohibit the EPA from regulating carbon dioxide and mercury from power plants, particularly if it was considered a trade-off. The plan was a critical piece of the Obama administration's successful efforts to forge the landmark Paris climate agreement previous year. A stay on the rule was issued by the U.S. Supreme Court was issued earlier this year. However, the outcome of the federal court case likely will end up with the U.S. Supreme Court. Tuesday's case was heard by all the active members of the court except for Chief Judge Merrick Garland who has recused himself from hearing cases because he has been nominated to the Supreme Court.
Six of the 10 judges were named by Obama or his Democratic predecessor, Bill Clinton, and most sharply questioned state and industry opponents. During the hearing, judges weighed the prospect of deferring to the EPA on the construction of the rule, or deciding that the CPP is such an important regulatory scheme that their intervention is justified. Still, the legal fight over Obama's signature effort to cut carbon pollution is unlikely to be settled before he leaves office.