In April 2007, the U.S. Supreme Court ruled 5 to 4 against the Environmental Protection Agency (EPA) in Massachusetts v. EPA. The lawsuit’s intent was to force the EPA to regulate CO2 and other greenhouse gases (GHG) as pollutants because of their supposed contribution to global warming. The basis of the suit was EPA’s contention in 2003 that it lacked the authority under the Clean Air Act (CAA) to regulate carbon dioxide (CO2).