The US Supreme Court has granted certiorari on this question: "Whether the Court should overrule Chevron or at least clarify that statutory silence concerning controversial powers expressly but narrowly granted elsewhere in the statute does not constitute an ambiguity requiring deference to the agency." Loper Bright Enterprises v. Raimondo (US S Ct cert granted 05/01/2023) [Briefs].

This heralds the end of deference under Chevron U.S.A. v. Natural Resources Defense Council, 467 U.S. 837 (1984). Chevron held that courts should defer to a federal agency’s interpretation of an ambiguous statute as long as that interpretation is reasonable.

In the Loper case, commercial fishing companies challenged a rule adopted by the National Marine Fisheries Service that requires fishing companies to pay for the costs of observers who monitor compliance with fishery management plans. The DC Circuit ruled (2-1) that the court should defer to the agency's interpretation. Loper Bright Enterprises v. Raimondo (DC Cir 08/12/2022) [Opinion]

In my opinion, Chevron died on March 4, 2019 in BNSF Railway v. Loos (US Supreme Ct 03/04/2019) [PDF]. That was a boring payroll tax case in which the IRS had interpreted a tax statute. In an opinion by seven Justices, there was NO mention of Chevron. See my blog on the BNSF case here.