Clean air's legal silver lining

In a decision that was a legal defeat for the Obama administration but that may well be a practical victory, the U.S. Supreme Court's conservative justices voted 5-4 to block the Environmental Protection Agency from a creative-yet-practical interpretation of the Clean Air Act that would have let the EPA significantly increase its regulation of greenhouse gases.

Nevertheless, in an opinion by Justice Antonin Scalia, the conservatives threw the EPA a bone, allowing regulation of greenhouse gases from plants that already emitted significant pollutants of other kinds.

The opinion's official message was that the EPA can't regulate specifically greenhouse-gas polluters unless Congress passes a new law. But in comments from the bench, Scalia said the EPA was getting "almost everything it wanted" — that it had sought to regulate 86 percent of greenhouse gases and that it would be able to regulate 83 percent.

The legal and regulatory background is devilishly complicated. Consider what follows a simplification by a nonexpert for readers who are nonexperts as well.

In 2007, in what seemed like a landmark case called Massachusetts vs. EPA, Justice Anthony Kennedy joined the court's four then-liberals in holding that the George W. Bush administration's EPA had not only the authority but also the obligation to regulate carbon dioxide and greenhouse gases, which until then had not been treated as "pollutants" under the relevant environmental laws. Environmentalists considered the case a major win for increased regulation that would combat climate change.

On Monday, the Supreme Court had to decide whether one of the plans the EPA adopted on the basis of that earlier case satisfied the requirement of the law. The particular program in question had to do with Title I of the Clean Air Act, which concerns major, stationary polluting sources. The way the act was written, it gave the EPA authority over stationary sources such as plants that emitted more than 250 tons a year of pollutants into the air. (This is, again, a simplification.)

Once the EPA got authority over greenhouse gases in 2007, however, the 250-tons-a-year standard no longer made practical sense. It turns out that vast numbers of plants produce more than 250 tons a year of carbon dioxide. Common sense required a higher number where this new pollutant was concerned. So the EPA picked one: It enacted a rule saying that it would regulate stationary sources that emitted more than 100,000 tons a year of carbon dioxide.

As a matter of statutory interpretation, however, the EPA's regulation was extremely iffy. The statute, after all, clearly set 250 tons a year of pollutant as its threshold.

This time around, Kennedy balked at joining the liberals. He voted with Scalia and the conservatives instead. Scalia's opinion acknowledged that the true definition of "air pollutant" is difficult under the Clean Air Act, which uses the term "promiscuously." Yet, Scalia insisted, the EPA could not simply adopt 100,000 tons as its standard when the statute said 250. If the EPA wanted to regulate greenhouse gases under Title I of the act, it would have to go back to Congress and ask for a change. This holding was consistent with Scalia's general philosophy of statutory interpretation, which emphasizes the plain meaning of the text. Nevertheless, the opinion did not overturn the 2007 case of Massachusetts vs. EPA — because, whatever the four conservatives may have wanted, Kennedy was not going to reverse his prior vote.

Scalia's theory of statutory interpretation did, however, apparently require him to acknowledge that where the EPA already has the authority to regulate stationary sources because they emit more than 250 tons a year of pollutants other than greenhouse gases, the EPA could now regulate greenhouse gases produced by the same polluters. (The opinion called them "anyway sources.") This part of the decision had, Scalia claimed from the bench, the practical effect of giving the EPA a real-world win alongside its legal loss.

Justices Samuel Alito and Clarence Thomas wouldn't even go that far. Alito wrote separately to say that Massachusetts vs. EPA was wrong when it was decided and that it was still wrong. As far as Alito was concerned, Scalia's opinion just showed how wrong the 2007 decision was. "Anyway sources" should not be regulated, either.

The liberals, of course, agreed that the "anyway sources" could be regulated. But they thought the EPA's creative statutory interpretation was fine. Justice Stephen Breyer wrote the dissent on their behalf. His explanation was straightforward, and it quoted the great midcentury judge Learned Hand as saying that the judge's job is to ascertain the statute's "underlying purpose," and then ask how reasonable people, "actuated" by the purpose, "would have dealt with it, if it had been presented to them at the time."

Scalia and the conservatives disagree: They think that the law is a kind of automatic command and that regulators can't play with it unless its meaning is genuinely ambiguous.

The debate is a hugely important one, and has loomed over the Supreme Court term. Monday Scalia's textualism was victorious. Feel the earth getting a little warmer?