Two of the Supreme Court’s major, end-of-term decisions turn on the deference the Court gives to agency determinations of the meaning of ambiguous clauses in complex regulatory statutes, applying the familiar Chevron framework.  The Court’s less deferential applications of Chevron raise important questions about the deference courts might be expected to give to the scope of EPA’s exercise, in its Clean Power Plan, of its statutory authority to establish carbon dioxide emission reduction standards for existing fossil-fuel power plants under Section 111(d) of the Clean Air Act.

In King v. Burwell, the Court reviewed an Internal Revenue Service regulation that allowed tax subsidies under the Affordable Care Act for insurance plans purchased on either a federal or state-created “Exchange.”  In Michigan v. EPA, the Court reviewed EPA’s threshold determination under Section 112 of the Clean Air Act that it was “appropriate and necessary” to initiate regulation of hazardous air pollutants emitted by power plants, without consideration of costs at that initial stage of the regulatory process.

The outcome in each case depended upon the Court’s review of the regulatory context of the applicable ambiguous statutory clause.  Since the context of Section 111(d) of the Clean Air Act differs markedly from the contexts of the Affordable Care Act and Section 112 of the Clean Air Act, the outcomes in King v. Burwell and in Michigan v. EPA do not likely portend the outcome of future court challenges of the Clean Power Plan.  However, the Court’s application of Chevron deference in these two cases may portend a strikingly less deferential judicial review of EPA’s Clean Power Plan than might have been expected under the traditional two-part test of Chevron.

Under Chevron, courts examine first whether a regulatory statute leaves ambiguity and, if so, courts are directed to defer to a federal agency’s reasonable resolution of the ambiguity in a statute entrusted to administration by that agency.  All of the Court’s majority and dissenting opinions in King v. Burwell and in Michigan v. EPA (except for Justice Thomas’s lone dissenting opinion questioning the constitutionality of Chevron deference) confirm the applicability of the traditional Chevron framework.  What stands out in these cases is that the Court’s majority opinions do not defer to the agency’s resolution of ambiguity.

Chief Justice Robert’s opinion for a 6-3 majority in King v. Burwell grounds Chevron in “the theory that a statute’s ambiguity constitutes an implicit delegation from Congress to the agency to fill in the statutory gaps.”  But, “in extraordinary cases,” the Court states that Congress may not have intended such an “implicit delegation.”  The Court holds the statutory ambiguity before it to be one of those extraordinary cases in which Congress has not expressly delegated to the respective federal agency the authority to resolve the ambiguity and, therefore, seemingly, zero deference is given by the Court to the applicable IRS regulation.  The Court explains that whether billions of dollars in tax subsidies are to be available to insurance purchased on “Federal Exchanges” is a question of “deep economic and political significance,” central to the scheme of the Affordable Care Act, such that had Congress intended to assign resolution of that question to the IRS “it surely would have done so expressly,” especially since the IRS “has no expertise in crafting health insurance policy of this sort.”  Eschewing any deference to the IRS interpretation, the Court assumed for itself “the task to determine the correct reading of” the statutory ambiguity.

King v. Burwell is the rare case in which the Court accords a federal agency zero deference in resolving statutory ambiguity under Chevron.  Notably, the Court left open how appellate courts should determine whether other statutory ambiguities similarly deserve less or no deference to agency interpretations.  The Court, perhaps, offered a hint by citing to its much quoted dicta in its 2014 decision in Utility Air Regulatory Group v. EPA that the Court “typically greet[s] … with a measure of skepticism, … agency claims to discover in a long-extant statute an unheralded power to regulate a significant portion of the American economy.”  Many commenters have opined, even before King v. Burwell, as to whether this dicta has implications for judicial review of the Clean Power Plan, which, it may be argued, has “deep economic and political significance” comparable to the Affordable Care Act.  However, EPA surely has longer experience, greater expertise and wider latitude in crafting policy under the Clean Air Act than the IRS has in crafting health insurance policy.  Given the Court’s strong precedent establishing that greenhouse gases are expressly within the scope of the Clean Air Act, appellate courts might distinguish King v. Burwell and apply traditional Chevron deference to the final Clean Power Plan.

Michigan v. EPA applies Chevron to EPA regulations under a different part of the Clean Air Act.  In this case, the Court reviewed EPA’s threshold determination, under Section 112 of the Clean Air Act, that it was “appropriate and necessary,” without regard to costs, to regulate hazardous air pollutants, such as mercury, from power plants.  The specific mercury emission limits imposed on categories of power plants were established during subsequent phases of EPA’s rulemaking under Section 112 based on EPA’s explicit consideration of costs.  Justice Scalia’s opinion for a 5-4 majority strikes down EPA’s determination that it could find regulation of hazardous air pollutants from power plants to be “appropriate and necessary” without consideration of costs.  The Court states it was applying the traditional Chevron framework, under which it would normally defer to EPA’s choice among reasonable interpretations of the  ambiguous and “capacious” statutory test requiring an EPA finding that regulation be “appropriate and necessary.”  But, the Court finds EPA’s interpretation of this test, as not requiring any consideration of costs, to “have strayed far beyond … the bounds of reasonable [statutory] interpretation.”  Michigan v. EPA may be the first case in which the Court has applied Chevron to find that EPA adopted an entirely unreasonable resolution of statutory ambiguity in its Clean Air Act regulations.

Justice Kagan’s dissent in Michigan v. EPA faults the Court for failing to give due deference under Chevron to EPA’s decision as to when in its regulatory process it gives consideration to the costs involved in regulating hazardous air pollutants from power plants.  While all nine Justices seem to agree that EPA must consider costs in its Section 112 rulemakings, and seem also to agree that EPA gave consideration to costs in later stages of its rulemaking, the dissent criticized the majority’s “micromanagement of EPA’s rulemaking,” emphasizing that EPA reasonably determined “that it was ‘appropriate’ to decline to analyze costs at a single stage of a regulatory proceeding otherwise imbued with cost concerns.”

It is difficult to predict whether, based upon King v. Burwell and Michigan v. EPA, appellate courts might narrow the deference accorded to EPA’s resolution of statutory ambiguities under Section 111(d).  Those ambiguities arise in a quite different context than those considered by the Court.  As one example, critics of the Clean Power Plan have argued that two different versions of Section 111(d) appear to have been signed into law, one of which critics claim should prohibit EPA from issuing regulations under Section 111(d) for sources of pollution already covered by other EPA regulations, such as hazardous pollutant regulation under Section 112.  EPA sharply disagrees with its critics and defends its interpretation of which statutory version applies and the scope of permissible regulation under either statutory text.  A related issue under the statutory version pressed by critics concerns whether the status of the hazardous air regulations under Section 112, during remand after Michigan v. EPA, should alter EPA’s analysis the potentially competing statutory provisions.  It remains to be seen what kind of Chevron deference courts will give to EPA’s reasoned interpretations of the different versions of Section 111(d).

Critics also point to purported ambiguity in Section 111(d) as to whether EPA may prescribe carbon dioxide performance standards based on so-called “outside the fence” measures, and whether those standards may be determined on an average state-wide basis, rather than for individual sources.  EPA’s resolutions of these and related programmatic issues have occasioned widespread commentary and may feature prominently in future court challenges to the Clean Power Plan.  Again, it remains to be seen whether the Court’s recent cases will influence the extent of Chevron deference given by appellate courts to EPA’s well-considered interpretation of its authority to craft the details of the Clean Power Plan under Section 111(d).

On one point, there should be little doubt.  Section 111(d) expressly directs EPA to consider costs in establishing performance standards reflecting “the best system of emission reduction.”  Unlike in Michigan v. EPA, EPA expressly addressed “costs” as a factor considered in its proposed rules.  EPA is expected to elaborate upon the costs (and benefits) of regulation in its final Clean Power Plan.  Michigan v. EPA should, therefore, be inapposite with respect to any possible challenges of the manner in which the Clean Power Plan addresses costs.

The applicability of Chevron deference is, of course, only one among many legal issues that could face the U.S. Courts of Appeals and, ultimately, the Supreme Court, if and when they review the Clean Power Plan.  The precise legal issues to be framed for the courts and the timing of litigation will not begin to come into focus until after the Obama Administration issues the final Clean Power Plan later this summer.  And, Congress could step in and alter the course of judicial review.  Stay tuned.