On June 23, 2014, the U.S. Supreme Court released its opinion in Utility Air Regulatory Group v. EPA. Justice Scalia wrote the majority in which Chief Justice Roberts and Kennedy joined in full. Justices Thomas and Alito joined the part of the opinion (5-4) rejecting EPA’s conclusion that sources are required to obtain Prevention of Significant Deterioration (PSD) or Title V permits on the sole basis of their potential greenhouse gas (GHG) emissions and finding that EPA lacked the authority to issue the Tailoring Rule. Justices Ginsberg, Breyer, Sotomayor and Kagan joined the part of the opinion (7-2) that finds it reasonable for EPA to determine that sources that are otherwise subject to PSD review (i.e. “anyway source”) must also consider their GHG emissions.