The Court of Appeals for the District of Columbia Circuit issued an opinion this morning upholding EPA’s greenhouse gas regulations.  Most importantly, the court held that GHGs are "subject to regulation" under the Clean Air Act, but that none of the petitioners had standing to challenge the Timing or Tailoring rules for stationary sources.  Coalition for Responsible Regulation, Inc. v. United States Environmental Protection Agency, No. 09-1322 (D.C. Cir. June 26, 2012).  

Michael Cooke of GT Tampa has posted a more in-depth analysis here.