On June 20, 2011, the United States Supreme Court issued a decision reversing the decision of the U.S. Court of Appeals for the Second Circuit, which had held that federal common law provides a basis for eight states, New York City, and three nonprofit organizations to seek reductions in greenhouse gas emissions from large coal-fired power plants. American Electric Power Co. v. Connecticut, No. 10-174 (June 20, 2011).
The unanimous Court, in an opinion written by Justice Ginsburg, held that the Clean Air Act displaces federal common law claims seeking abatement of greenhouse gas emissions. Justice Sotamayor recused herself, having sat on the Second Circuit panel that heard oral arguments in the case.