At the bottom of the Supreme Court’s decision today tossing out, in large part, the Obama Administration’s greenhouse gas emissions scheme is a stiff dose of constitutional common sense: “When an agency claims to discover in a long-extant statute an unheralded power to regulate a significant portion of the American economy, we typically greet its announcement with a measure of skepticism.”

Here, skepticism was certainly warranted. At issue was one of the Obama Administration’s earliest efforts to skirt Congress and achieve its major policy goals unilaterally through aggressive executive action.

A bit of background is necessary. The Clean Air Act’s 1970’s-era “Prevention of Significant Deterioration” and “Title V” programs are aimed at the few hundred largest industrial sources of pollution in the country and impose what the Court correctly identified as “heavy substantive and procedural burdens,” far beyond the red tape that most businesses are able to shoulder. To that end, the statute limits regulation to sources that emit more than 100 or 250 tons per year of certain “air pollutants.”

EPA’s trick was to redefine “air pollutant,” as used in those programs, to include carbon-dioxide emissions. Because carbon-dioxide is emitted in large quantities even by smaller sources, that interpretation expanded the number of sources subject to regulation from a few hundred to millions altogether. Regulations that had previously been confined to major power plants, chemical factories, and the like would now apply to retail stores, offices, apartment buildings, shopping centers, schools, and churches. To avoid what even EPA recognized to be an “absurd result,” the agency went on to claim authority to decide exactly which sources have to comply—in other words, the power to choose winners and losers by exempting the vast majority of sources from compliance, for the time being at least. It called this approach “tailoring.” 

The Court, in a lead opinion by Justice Scalia, called it “patently unreasonable—not to say outrageous.” EPA, it held, must abide by the statute: “An agency has no power to ‘tailor’ legislation to bureaucratic policy goals by rewriting unambiguous statutory terms.” And if such tailoring is required to avoid a plainly “absurd result” at odds with congressional intentions, then obviously there is obviously something wrong with the agency’s interpretation of the statute. To hold otherwise, the Court recognized, “would deal a severe blow to the Constitution’s separation of powers” by allowing the executive to revise Congress’s handiwork.

The loss for the administration was not complete. The Court did allow that EPA can regulate greenhouse emissions by newly-built (or substantially modified) sources that would already be subject to PSD or Title V without taking into account their greenhouse gas emissions—known as “anyway sources.” But even this authority, the Court explained, is not “unbounded” and does not authorize to EPA to mandate any manner of efficiency gain.

The Court’s decision may be a prelude of more to come. Since the Obama Administration issued its first round of greenhouse gas regulations, it has become even more aggressive in wielding executive power so as to circumvent the need to work with Congress on legislation. That includes recent actions on such issues as immigration, welfare reform, and drug enforcement. It also includes new regulations for greenhouse gas emissions by power plants, proposed just this month, that go beyond traditional plant-level controls to include regulation of electricity usage and demand—that is, to convert EPA into a nationwide electricity regulator. Today’s decision—as well as one last month by the D.C. Circuit rejecting a nearly identical regulatory gambit by the Federal Energy Regulatory Commission—suggests that this won’t be the last court decision throwing out Obama Administration actions as incompatible with the law.