It should be obvious that the EPA must obey the law. However, the EPA and every other regulatory agency has long adopted the principle that they can exercise whatever flights of fantasy they wish in interpreting the laws passed by Congress that the agency has been empowered to enforce. The EPA has declared that carbon dioxide is a pollutant under the Clean Air Act and claimed that that gave it the power to control its emissions from power plants. Carbon dioxide was certainly not considered a pollutant when the Clean Air Act was passed into law. It was declared a pollutant by the EPA under the Obama administration under the claim that it caused catastrophic man-made global warming. That declaration of carbon dioxide as a pollutant had particularly threatening effects upon existing coal-fired power plants. The Supreme Court put a temporary hold on the Obama EPA rules for carbon dioxide emissions from power plants. In 2017, the Trump EPA changed those rules to make them more lenient, but the U.S. Court of Appeals for the District of Columbia decided the Trump EPA rules were invalid. This caused West Virginia and 18 other states to appeal that ruling to the Supreme Court.
If carbon dioxide actually did cause catastrophic man-made global warming, that would still not actually make it a pollutant and it would not really have been addressed by the Clean Air Act. The EPA is required to provide scientific studies proving that an emitted gas is a pollutant. The EPA cited no actual science proving that carbon dioxide caused catastrophic man-made global warming. It did point at the UN IPCC reports, but those reports are only political documents fulfilling the desires of the governments of the world. They are not scientific analyses, though they mascaraed as such. The Summary for Policymakers for each report is written by the political representatives of the governments and any failures of the more detailed "science" sections of the report to support the political Summary for Policymakers are corrected as required. There have been many re-writes of the science sections to make them more supportive of the political ends of the governments. Nonetheless, the unwarranted assumptions and the holes in the scientific argument for catastrophic man-made global warming are apparent to any careful reader of the "science" sections of the UN IPCC reports. Over the years, many of the scientists who wrote the original science sections stopped participating in the writing of the IPCC reports because they were furious about how the science sections were rewritten either by the scientists on the take or by purely political hacks.
In a 6 - 3 ruling, written by Chief Justice Roberts, the Supreme Court said that it was implausible that the Congress would have given the EPA the power to control carbon dioxide emissions of power plants without saying so clearly and explicitly in the Clean Air Act. He also said that such controls have such a strong effect upon our energy service that such a power requires that Congress address it in law explicitly if those controls are entrusted to a government agency. Indeed, the implication was that any agency making decisions with great magnitude and consequence must have been given that power very explicitly by our elected representatives.
This ruling is of huge importance for American energy infrastructure and the cost and reliability of power for Americans. It will likely also result in a welcome reduction of regulatory overreach so common for most of our government regulatory agencies. It will force Congress to make laws addressing many issues for which they might rather not take responsibility. The rate of new rulings of government agencies far surpass the rate of new laws produced by Congress. This court ruling will serve as a brake on the rapid growth of government micromanagement of most all aspects of our lives.
I propose we make 30 June a national holiday called Freedom from Regulation Day.