Last week the United States Court of Appeals for the District of Columbia heard arguments challenging the Environmental Protection Agency’s effort to regulate greenhouse gas emissions from existing power plants. The Clean Power Plan, as it is called, is central to President Barack Obama’s overall Climate Action Plan. West Virginia and Texas are leading the 27 states and state agencies now in opposition to the CPP regulations, and some 120 companies and organizations have filed in support of the coalition’s complaint.

CPP is designed to bring about what the EPA calls an “aggressive transformation” of electricity generation throughout the country. It would do this by systematically “decarboniz[ing]” power generation and ushering in a new “clean energy” economy less reliant on carbon. CPP requires that, by 2030, power-plant carbon emissions be reduced by a third from what they were in 2005.