Cross-posted from ThinkProgress.

Monday morning’s Supreme Court decision in American Electric Power Co. vs. Connecticut [PDF] is undoubtedly a setback for the environment. The plaintiffs, which included several states and the city of New York, sought to reduce greenhouse-gas emissions under a legal theory known as “nuisance” which would allow federal courts to intervene against five of the nation’s worst polluters, and the justices voted eight to zero to deny federal judges that power (Justice Sonia Sotomayor was recused).

Yet there are two silver linings for environmentalists in the opinion. One is the court’s entirely sensible conclusion that the best environmental policy is made by people with actual expertise in climate science:

It is altogether fitting that Congress designated an expert agency, here, EPA, as best suited to serve as primary regulator of greenhouse gas emissions. The expert agency is surely better equipped to do the job than individual district judges issuing ad hoc, case-by-case injunctions. Federal judges lack the scientific, economic, and technological resources an agency can utilize in coping with issues of this order.

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Indeed, there is a very good reason why the federal Clean Air Act imposes a duty on environmental policy experts within the EPA to regulate greenhouse gases. Climate science is complex, and non-experts such as judges or members of Congress will find it difficult to sort the good studies from the pseudoscience and reach informed policy decisions. Indeed, the many climate change deniers in Congress serve as a constant reminder of the wisdom of the Clean Air Act’s decision to delegate environmental policy to actual experts.

The other silver lining comes at the end of the opinion. While the justices held that federal judges must defer to an expert agency, they left open the possibility of state lawmakers or judges stepping up to fill any holes in environmental regulation that EPA does not or cannot fill. These state laws will inevitably be challenged by polluting industries, and they will present a real dilemma for conservatives who claim to revere the 10th Amendment. Either states have the right to set their own policy, or they don’t — and conservatives’ reaction to state environmental laws will be a very real test of whether they really care about states rights, or if they simply believe that the Constitution means whatever they want it to mean at the moment.

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