The U.S. Supreme Court ruled 6-2 this morning in favor of the Environmental Protection Agency in a case testing the EPA's powers to interpret and enforce an "ambiguous" provision of the Clean Air Act. According to the majority opinion of Justice Ruth Bader Ginsburg, "we read Congress' silence as a delegation of authority to EPA to select from among reasonable options."
The case originated with the problem of regulating air pollution that travels from "upwind" states to "downwind" states. According to the Court, "EPA must have leeway in fulfillng its statutory mandate" to combat this problem. "We routinely accord dispositive effect to an agency's reasonable interpretation of ambiguous statutory language," declared Justice Ginsburg, in a ruling joined by Chief Justice John Roberts and Justices Anthony Kennedy, Stephen Breyer, Sonia Sotomayor, and Elena Kagan (Justice Samuel Alito was recused).
Writing in dissent, Justice Antonin Scalia, joined by Justice Clarence Thomas, fired back at the majority's deference to the EPA. "Too many important decisions of the Federal Government are made nowadays by unelected agency officials exercising broad lawmaking authority, rather than by the people's representatives in Congress," Scalia declared.
The opinion in EPA v. EME Homer Air City Generation is available here.