Divided Court rejects EPA regulation limiting hazardous emissions from power plants

Judicial deference to agency interpretations of ambiguous statutory terms—a doctrine established in Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984)—is one of the fundamental underpinnings of the modern administrative state. It has been particularly critical to the development of environmental regulations. Chevron deference has allowed Congress to paint its environmental goals in broad terms, in statutes like the Clean Air Act and the Clean Water Act, while leaving to the U.S. Environmental Protection Agency (EPA) the task of both determining what precisely Congress intended in those statutes and how exactly to achieve what the agency perceives to have been Congress’s goals. It has also allowed successive administrations considerable leeway to change course in environmental policy, simply by proffering and rationally explaining new interpretations of ambiguous statutory provisions.