With Chief Justice Roberts writing for a six-Justice majority, the Court overruled Chevron, holding that the Administrative Procedure Act (APA) requires courts to exercise their independent judgment in deciding whether an agency has acted within its statutory authority, and courts may not defer to an agency’s legal interpretation simply because a statute is ambiguous. Justice Thomas and Justice Gorsuch concurred. Justices Kagan, Sotomayor, and Jackson dissented.

The majority opinion: The majority explained that, from the start, the Framers envisioned that courts would be the final authority on what the law says. To quote Marbury v. Madison, “[i]t is emphatically the province and duty of the judicial department to say what the law is.” The APA was consistent with that approach: It requires courts to decide legal questions and does not mandate any deference to agencies. The deference Chevron required therefore cannot be squared with the APA. The Court also rejected the concept that “statutory ambiguities are implicit delegations to agencies.” An ambiguity may result from Congress’s inability to answer the question or a failure to consider it entirely. And when courts confront statutory ambiguity in other contexts, they resolve it there is no reason to take a different approach simply because an ambiguity involves an executive agency. But when Congress has expressly delegated the power to interpret a statutory term to an agency – either expressly or through a term implying delegation, such as “reasonable” or “appropriate” – courts must review the agency’s action under the more deferential arbitrary-and-capricious standards.

The Court also rejected the idea that agencies have special expertise that can assist with resolving statutory ambiguity. Courts hold that expertise – and there is no reason to think Congress intended to transfer that authority to the Executive Branch. The Court emphasized that courts can still look to the agency’s expertise as “informative.” The Court downplayed concerns that jettisoning Chevron would create inconsistency in the law or that would invite judges to engage in unlicensed policymaking. The majority also emphasized that Chevron was replete with practical difficulties. The doctrine had evolved to include many steps and sub-steps over time and was riddled with exceptions and limits. Indeed, the Supreme Court had not deferred to an agency’s interpretation under Chevron since 2016.

Finally, the majority held that stare decisis – which governs when the judiciary will adhere to prior precedent – did not require retaining Chevron. “Chevron ha[d] proved fundamentally misguided” and “unworkable.” It was impossible to define how much “ambiguity” must exist before the court will consider deferring to an agency or to define what constitutes a “reasonable” interpretation, such that deference was warranted. Because there could be multiple “reasonable” interpretations, Chevron also allowed agency flip-flopping, destroying reliance interests. The Court stressed, however, that previous cases holding “specific agency actions are lawful – including the Clean Air Act holding of Chevron itself” would still be subject to stare decisis.

Justice Thomas and Justice Gorsuch’s concurrences: Justice Thomas and Justice Gorsuch joined the majority and also each wrote separately. Justice Thomas stressed that Chevron was not just unlawful under the APA; it is also unconstitutional because it violates the separation of powers by requiring judges to abdicate their constitutional duty to resolve statutory ambiguity. Chevron also unduly authorized the Executive Branch to exercise powers not given to it.

Justice Gorsuch shared his view that stare decisis did not require adhering to Chevron. First, he reasoned that the Supreme Court is not bound under stare decisis to adhere to a decision that departs from the Constitution or laws of the United States, and Chevron violates the text of the APA. Second, although past judicial decisions merit respect, “judicial humility” required recognizing the limits of those past decisions – especially here, where Chevron was “jarringly inconsistent” with many other longstanding precedents on the role of the judiciary in resolving textual disputes, and Chevron had proved unworkable in practice. Third, judicial opinions are meant to be narrow and specific to the facts of a particular case, and Chevron has morphed over time to something far more than it was originally.

Justice Kagan, Sotomayor, and Jackson’s dissent: The dissent would have upheld Chevron deference. The dissenters argued that rule was correct, workable, and appropriate, and the majority’s decision overruling Chevron displayed a shocking lack of humility and self-awareness. The background presumption of Chevron was that Congress wanted agencies, not courts, to make judgment calls in the face of ambiguities. That makes sense. There are many questions that are not within the competence of courts, and which should be left to the subject-matter expert agencies – like whether and when an “alpha amino acid polymer” qualifies as a “protein” under the Public Health Service Act, or whether one population of squirrels is “distinct” from another under the Endangered Species Act. These are, at bottom, policymaking decisions. Chevron thus reflected an appropriate balance of power between the branches.

The dissent also argued that Chevron is far narrower than the majority suggests, comports with the APA, has consistently been used and relied on by litigants and lower courts, set forth a sensible default rule, is workable, and should be upheld under stare decisis. The dissent stressed that Congress was well aware of Chevron and had done nothing to displace it. The dissent accused the majority of artificially engineering Chevron’s demise by steadfastly refusing to apply the doctrine for the last eight years, so that it could now say the doctrine was unimportant because the Supreme Court had not applied it for the last eight years. Finally, the dissent concluded by reiterating that the majority’s decision fundamentally shifts the separation of powers from the Executive to the Judiciary, consistent with the Court’s broader practice of “roll[ing] back agency authority, despite congressional direction to the contrary.”

Authored by Sean Marotta and Danielle Desaulniers Stempel.