But Justice Breyer’s remark nonetheless underscored a split on the court over whether to defer to expert agencies or to insist on independent judicial review of their actions.

The precise question in the case was whether the court should overrule a pair of decisions that required judges to defer to agencies’ reasonable interpretations of their own ambiguous regulations. The decisions — Bowles v. Seminole Rock & Sand Co. in 1945 and Auer v. Robbins in 1997 — have been the subject of much criticism, and several justices have urged the Supreme Court to revisit them.

Justice Elena Kagan, perhaps thinking of other decisions that may be at risk as well, said the court should not lightly overrule its precedents. “We need a good reason for it,” she said, particularly when Congress is free to address the matter. “I mean,” she said, “we used to.”

The case, Kisor v. Wilkie, No. 18-15, concerned a regulation of the Department of Veterans Affairs concerning disability benefits. In ruling against James Kisor, who served in Vietnam as a Marine and later received a diagnosis of post-traumatic stress disorder, a federal appeals court relied on the department’s interpretation of one of its regulations.

Paul W. Hughes, a lawyer for Mr. Kisor, said that shifting agency interpretations, made without notice to the public or comment from it, were at odds with federal law and fairness.