Kisor v. Wilkie

Supreme Court of the United States · 2019 · Administrative Law

588 U.S. 558 (2019)

Updated August 1, 2026

Administrative LawAuer deference limitsagency interpretationsgenuine ambiguitytraditional tools of constructionreasonablenessauthoritative positionagency expertise

Facts

Kisor, a Vietnam War veteran, originally sought VA disability benefits for PTSD in 1982, but the VA denied the claim after finding he did not suffer from PTSD. In 2006, he moved to reopen the claim, and the VA granted benefits based on a new psychiatric report, but only from the reopening date rather than from 1982. A VA regulation allowed retroactive benefits if the agency later found previously unconsidered 'relevant official service department records.' Kisor produced two new service records confirming his participation in Operation Harvest Moon, but the Board concluded they were not 'relevant' because they did not address the original ground for denial: lack of a PTSD diagnosis.

Issue

Should the Court overrule Auer and Seminole Rock deference to agencies' reasonable interpretations of their own genuinely ambiguous regulations? If not, under what limits may a court defer to an agency's interpretation of its own regulation, and did the Federal Circuit apply those limits correctly here?

Rule

Auer deference remains valid, but it applies only in limited circumstances. A court may defer to an agency's interpretation of its own regulation only if the regulation is genuinely ambiguous after the court exhausts all traditional tools of construction; the agency's interpretation is reasonable and within the zone of ambiguity; and the interpretation is the agency's authoritative or official position, implicates the agency's substantive expertise, and reflects its fair and considered judgment without creating unfair surprise to regulated parties.

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One of 10 multiple-choice questions for this case. Pick an answer to see why.

The Coastal Habitat Bureau has a regulation requiring permit applicants to submit a "complete site map" before dredging work in Charleston, South Carolina. In a dispute with Harbor Reed LLC, the agency argues that "complete" includes nearby parcels owned by affiliates, while Harbor Reed argues it includes only the project parcel. After examining the text, surrounding provisions, and the regulation's stated purpose, a court concludes the regulation plainly refers only to the project parcel.

How should the court treat the agency's interpretation?

Explanation. A court may not give Auer deference unless the regulation is genuinely ambiguous after exhausting all traditional tools of construction. If the court's analysis of text, structure, history, and purpose yields only one reasonable meaning, the court must enforce that meaning and cannot defer to a different agency view.