Loper Bright Enterprises v. Raimondo

In a 6–3 decision authored by Chief Justice John Roberts, the Supreme Court overruled the Chevron doctrine. The Court held that federal courts must exercise their own independent judgment when interpreting federal statutes, even when those statutes are ambiguous, and may not simply defer to an agency's interpretation merely because the statute is unclear. This effectively ended the 40-year-old practice of courts stepping aside and letting agencies have the last word on what ambiguous laws mean.

The majority grounded its reasoning primarily in the text and history of the Administrative Procedure Act (APA) of 1946. Section 706 of the APA instructs reviewing courts to 'decide all relevant questions of law' and to 'determine the meaning or applicability of the terms of an agency action.' Chief Justice Roberts wrote that this language reflects the traditional understanding that interpreting statutes is a core judicial function — and that Chevron had improperly required courts to surrender that function whenever a statute was deemed ambiguous. The Court emphasized that the APA was enacted precisely to ensure meaningful judicial review of agency action, not to create a presumption that agencies get to define the scope of their own power.

The majority also invoked broader constitutional principles rooted in the separation of powers. Under Article III, it is the province of the judiciary to say what the law is — a principle stretching back to Marbury v. Madison. Chevron, the Court found, had turned this principle on its head by effectively making agencies the primary interpreters of federal statutes, with courts playing only a secondary, deferential role. The majority argued this arrangement was particularly problematic because it allowed agencies to expand their own authority by adopting broad readings of the statutes they administer.

Importantly, the Court drew a distinction between two different situations. When a statute is genuinely ambiguous and a court must determine its best reading, the court should do so using traditional tools of statutory interpretation — it should not defer to the agency. However, when Congress has expressly delegated authority to an agency to define a specific term or fill in a particular detail, courts should respect that delegation and review the agency's action accordingly, typically under an arbitrary-and-capricious standard. In other words, Congress can still give agencies discretion to make certain policy choices, but the question of whether Congress actually granted that discretion in any given case is one for courts to answer independently.

The Court also addressed concerns about the thousands of prior decisions that had relied on Chevron. It stated that those decisions were not automatically called into question simply because Chevron was overruled. Prior cases that relied on the Chevron framework still carry the force of statutory stare decisis — that is, the specific statutory interpretations adopted in those cases remain the law unless and until they are revisited through the normal legal process.