Does the new energy legislation and the EPA's decision to deny California a waiver under the Clean Air Act have any effect on the federal government's plans to adopt federal controls on vehicular emissions of greenhouse gases? Perhaps. A key provision in the new energy bill requires an increase in automotive fuel economy over the coming decades. One effect of these standards will be a reduction in automotive emissions of carbon dioxide. Given the effect of this provision, it might provide the Administration with a convenient excuse not to proceed with federal GHG emission regulations in response to Massachusetts v. EPA.

Is this just speculation? Maybe not. The tail end of this Washington Post story on the denial of California's waiver request contains this little tidbit:

When asked whether the energy law represents the administration's full response to the challenge of global warming, [EPA Administrator Johnson] replied, "Certainly for motor vehicles this is a comprehensive solution."

Given this reply, I would not be at all surprised were the EPA's response to Mass v. EPA nothing more than the adoption of regulations that track the fuel economy requirements of the new energy legislation, but achieve no additional reductions. If so, this is another EPA decision on climate change policy that could end up back in court.

UPDATE: The LA Times reports the Administration is reconsidering its obligation to set federal greenhouse gas emission standards for new motor vehicles in light of the new energy legislation. While I would be surprised were the administration to do nothing at all, I would not be at all surprised to see the EPA issue federal emission controls that track the fuel economy requirements of the new energy law, and this would achieve the same result as doing nothing at all.