On Monday, Feb. 24, 2014, the Supreme Court heard oral arguments in Utility Air Group v. EPA, the consolidation of six cases challenging the Environmental Protection Agency’s ability to regulate greenhouse gas emissions from stationary sources like power plants.  For 34 years, EPA has—under the Clean Air Act authority that allows the agency to regulate “any air pollutant”—regulated not just air pollution itself, but the source of that air pollution.

In 2007, the Supreme Court upheld the EPA’s authority to regulate greenhouse gases emitted by mobile sources in the case Massachusetts v. EPA.  Following up on the Mass. v. EPA decision, the EPA in 2010 concluded that it should regulate pollution from cars and trucks.  The EPA then used that finding to “trigger” regulations of stationary sources, such as power plants.  A 2011 Supreme Court case, American Electric Power v. Connecticut, unanimously affirmed that Congress meant to include greenhouse gases as an “air pollutant” under the Clean Air Act, and that the EPA must do something about greenhouse gas pollution.

Although this case is titled Utility Air Group v. EPA, there are actually many petitioners.  Utility Air Group is among the many private parties—mostly industry groups—represented in the case, and in the clips below all of these private parties are represented in oral argument by attorney Peter Keisler.  There were also several states that filed in opposition to the EPA, and those states received fifteen minutes of oral argument time, represented by the Solicitor General of Texas, Jonathan Mitchell.  Solicitor General Donald Verrilli represented the EPA in oral arguments.

The lone question that the Court will decide is whether the Clean Air Act permits the EPA to use the legal regime for mobile sources as a “trigger” for creating an analogous regulatory regime for stationary sources.  If the Supreme Court broadly decides against the EPA’s regulatory authority, it could severely limit the EPA’s ability to regulate pollution in the face of global warming.