“An agency has no power to ‘tailor’ legislation to bureaucratic policy goals by rewriting unambiguous statutory terms,” the Supreme Court declared Monday in Utility Air Regulatory Group v. EPA, rejecting the Obama administration’s unprecedented claim of executive power under the Clean Air Act (CAA).

Justice Antonin Scalia wrote for the Court, “EPA’s interpretation is also unreasonable because it would bring about an enormous and transformative expansion in EPA’s regulatory authority without clear congressional authorization.” His opinion was joined in full by Chief Justice John Roberts and Justice Anthony Kennedy. Part of his opinion was joined by the other conservative justices, while another part was joined by the liberal justices.

In its 2007 case Massachusetts v. EPA, the Supreme Court by a 5-to-4 decision held that the Environmental Protection Agency could regulate carbon dioxide and other so-called greenhouse gases as pollutants. The decision was hailed by liberals and condemned by conservatives as judicial activism, by which the Court was making a policy judgment about global warming and ignoring the terms of Congress’s laws.  

Referencing the Court’s 2007 decision (from which he has dissented), Scalia noted:

The Act-wide definition says that an air pollutant is “any air pollution agent… including any physical, chemical, biological, or radioactive… substance or matter which is emitted into or otherwise enters the ambient air.” In Massachusetts, the Court held that the Act-wide definition includes greenhouse gases because it is all-encompassing; it “embraces all airborne compounds of whatever stripe.”

Trimming back the reach of the 2007 decision, Scalia noted that in several places CAA indicated EPA’s reach is more limited than that general definition, reasoning that the context of each provision can limit its effect. So for those, “the statute is not using ‘air pollutant’ in Massachusetts‘ broad sense to mean any airborne substance whatsoever.”

“EPA must ground its action or inaction in the statute, rather than reasoning divorced from the statutory text,” Scalia continued. The Court continued pulling back its Massachusetts decision, finding the relevant CAA provision “is not a command to regulate, but a description of the universe of substances EPA may consider regulating.”

The Court gave voice to years of conservative criticism of the CAA’s reach. “To be sure, Congress’s profligate use of ‘air pollutant’ where what is meant is obviously narrower than the Act-wide definition is not conducive to clarity,” Scalia said.  

The Court added that even under the usual “deferential framework” for interpreting regulations implementing a federal statute, “agencies must operate within the bounds of reasonable interpretation.” As a consequence, “an agency interpretation that is inconsistent with the design and structure as a whole does not merit deference.”

The pugnacious Scalia then unloaded on the results the Obama administration’s arguments would produce:

EPA itself has admitted “the calamitous consequences of interpreting the Act in that way. Under the [EPA’s] program, annual permit applications would jump from about 800 to nearly 82,000; annual administrative costs would swell from $12 million to over $1.5 billion; and decades-long delays in issuing permits would become common, causing construction projects to grind to a halt nationwide.

Rejecting such a shocking power grab, the Court ruled it would not allow such power “when an agency claims to discover in a long-extant statute an unheralded power to regulate a significant portion of the American economy. We expect Congress to speak clearly if it wishes to assign to an agency decisions of vast economic and political significance.”

That is especially true here, since “it would be patently unreasonable–not to say outrageous–for EPA to insist on seizing expansive power that it admits the statute is not designed to grant.”

In the context of this specific case in which the Obama administration inserted its own terms into Congress’s statute, Scalia wrote, “It’s hard to imagine a statutory term less ambiguous than the precise numeral thresholds at which the Act requires [the relevant types of] permitting. When the EPA replaced those numbers with others of its own choosing, it went well beyond the bounds of its statutory authority.”

The Court put this in the larger pattern of President Barack Obama’s refusing to implement provisions of a law by claiming enforce discretion. Scalia reasoned, “an agency may adopt policies to prioritize its expenditures within the bounds established by Congress. Nothing in [Supreme Court precedent] authorizes an agency to modify unambiguous requirements imposed by a federal statute. An agency confronting resource constraints may change its own conduct, but it cannot change the law.”

The majority then explained why the Obama administration’s argument cannot be tolerated by the Constitution. Scalia explained:

Were we to recognize the authority claimed by the EPA in the Tailoring Rule, we would deal a severe blow to the Constitution’s separation of powers. Under our system of government, Congress makes laws and the President, acting at times through agencies like EPA, “faithfully executes them.” The power of executing the laws necessarily includes both authority and responsibility to resolve some questions left open by Congress that arise during the law’s administration. But it does not include a power to revise clear statutory terms that turn out not to work in practice.

Applying that to CAA, “We conclude that EPA’s rewriting of the statutory thresholds was impermissible and therefore could not validate the Agency’s interpretation of the triggering provisions.”

On a separate issue on which liberal justices joined the opinion and two conservatives fell away, the Court held that for emission sources that are already subject to EPA regulation for other reasons, the EPA can require those sources to use BACT (“best available control technology”). “We are not talking about extending EPA jurisdiction over millions of previously unregulated entities, but about moderately increasing the demands EPA… can make of entities already subject to its regulation.”

In this part on which the four liberal justices joined but conservatives Thomas and Alito disagreed, the Court held narrowly that the BACT requirements are legal on their face because they’re not “disastrously unworkable.” Even then, those seven justices required that such sources can only be regulated if they emit a significant amount of greenhouse gases. They left open the possibility that if EPA imposed overly-restrictive BACT regulations, then affected companies could file suit.  

Justice Stephen Breyer wrote separately for the four liberal justices, dissenting from the part of the Court’s opinion that invalidated the EPA rule and limited executive power. “That sort of decision, which involves the Agency’s technical expertise and administrative experience, is the kind of decision that Congress typically leaves to the agencies to make,” Breyer argued.

Justice Samuel Alito, joined by Justice Clarence Thomas, likewise wrote an opinion that concurred with most of Scalia’s opinion and dissented from the part allowing the BACT regulations. Alito began by writing, “Massachusetts v. EPA was wrongly decided at the time, and these cases further expose the flaws with that decision.”

Alito concluded a thorough criticism of the BACT regulations by reasoning, “BACT analysis, like the rest of the Clean Air Act, was developed for use in regulating the emission of conventional pollutants and is simply not suited for use with respect to greenhouse gases.”

Many media outlets have adopted (either mistakenly or deliberately) the spin of some liberal legal commentators, noting that EPA can still regulate the majority of greenhouse gas emitters it sought to regulate.

But that misses the much larger point that if EPA can change the numbers Congress writes into a statute, such power can be exerted to every area of federal regulation. The Court’s complete rejection of that unprecedented claim of executive power was a firm rebuke of the Obama administration.

Ken Klukowski is senior legal analyst for Breitbart News and a fellow with the American Civil Rights Union. Follow him on Twitter @kenklukowski.