Last week, Acting Solicitor General Edwin Kneedler filed a motion informing the Supreme Court that the federal government is no longer seeking review of New Jersey v. EPA, in which the U.S. Court of Appeals for the D.C. Circuit invalidated the Bush Administration's controversial mercury rule that sought to create a cap-and-trade system for mercury emissions from coal-fired utilities. Instead, Kneedler informed the justices, the Obama Administration would develop new regulations in accord with the appeals court ruling.

SCOTUSBlog notes that this is a "fairly radical policy reversal for the EPA." That it is, but not because it changes the ultimate outcome. As I noted here, the Bush EPA's mercury rule was quite flawed, and almost certainly illegal under the Clean Air Act. Thus even had the Court accepted cert in the case, a victory for EPA seemed quite unlikely, and the Obama Administration would have to develop new rules. The justices could still take the case, as an industry-backed cert petition is still pending for Friday's conference, but the odds this case will be accepted would seem to have dropped quite dramatically. So the primary effect of this decision is to accelerate the timetable for developing new mercury rules.

Meanwhile, the Bush Administration finally scored a victory (albeit somewhat belatedly) in a lower profile Clean Air Act case, South Coast Air Quality Management District v. EPA. On Friday, the D.C. Circuit rejected an environmentalist challenge to the EPA's failure to develop more stringent emission standards for large marine diesel engines in a more timely fashion. Given the number of times federal courts of appeals have struck down Bush Administration air rules, this seems significant, even if the case is relatively minor. More on the decision here.

UPDATE: As Law Dork Chris Geidner notes, the EPA's reversal is welcome news to some states -- those that opposed the Bush EPA mercury rule -- but not to others.