Today, June 30, the U.S. Supreme Court ruled in favor of 19 states hoping to review the scope of the U.S. Environmental Protection Agency’s (EPA) authority to regulate greenhouse gas emissions. The question at hand in West Virginia v. Environmental Protection Agency (EPA) was whether or not Congress granted the EPA authority in the Clean Air Act to issue significant rules, including those capable of reshaping the nation’s electricity grids and decarbonize any sector.

In its 6-3 ruling, the Supreme Court said Congress has this authority, not the EPA.

Chief Justice John Roberts delivered the majority opinion, with Justices Clarence Thomas, Samuel Alito, Neil Gorsuch, Brett Kavanaugh, and Amy Coney Barrett joining him. In his opinion, he said the court needed to determine whether the “best system of emission reduction” the EPA identified in the Clean Power Plan was within its authority granted in the Clean Air Act. He said it was not. “Congress did not grant EPA in Section 111(d) of the Clean Air Act the authority to devise emissions caps based on the generation shifting approach the agency took in the Clean Power Plan,” he said.

He also pointed out the EPA’s history of increasing its authority for “extraordinary cases,” which provided a “reason to hesitate before concluding that Congress” meant to confer such authority.

In his opinion, he said the EPA’s view of Section 111(d) was that Congress tasked it, and it alone, with balancing the many vital considerations of national policy implicated in the basic regulation of how Americans get their energy. “And this court doubts that Congress… intended to delegate … decision[s] of such economic and political significance, i.e., how much coal-based generation there should be over the coming decades, to any administrative agency,” he added.

The National Mining Association (NMA) applauded the ruling. “We are pleased to see the court confirm that there are limits to the authority that administrative agencies have to unilaterally issue transformative rules, particularly those that impose deep and uneven economic impacts on every state and industry across the country,” the NMA said. “While many would have liked to label this as a case about climate, it is not; it is a case about the authority of government agencies and the economic impacts to the states and all Americans when that authority is abused.”

The Clean Power Plan, which was enacted under former President Barack Obama’s administration, was stayed in 2016, preventing the rule from taking effect. It was repealed when former President Donald Trump took office. In 2019, the EPA replaced the Clean Power Plan with the Affordable Clean Energy.

A number of states and private parties filed petitions for review in the D.C. Circuit, challenging the EPA’s repeal of the Clean Power Plan and its enactment of the replacement ACE rule. The Court of Appeals consolidated the cases and held that EPA’s repeal of the Clean Power Plan rested critically on a mistaken reading of the Clean Air Act — that generation shifting cannot be a “system of emission reduction” under Section 111. The court vacated the agency’s repeal of the Clean Power Plan and remanded it to the agency for further consideration. It also vacated and remanded the ACE rule for the same reason.