Massachusetts v. EPA, US Supreme Court, April 2, 2006 [ruling that the Environmental Protection Agency has the authority under the Clean Air Act to regulate the emission of "greenhouse gases," such as carbon dioxide, by automobiles]. Read the court's 5-4 opinion [text] per Justice Stevens, along with a dissent [text] from Justice Roberts and a second dissent [text] from Justice Scalia. Reported in JURIST's Paper Chase here.