An interpretation by a government agency of its own mandate from Congress is entitled to judicial deference if the authority is ambiguous and the agency's interpretation is permissible under the statute, regardless as to whether it is the best possible interpretation or an interpretation the Court would have made. (Overruled by Loper Bright Enterprises v. Raimondo (2024)) Decided June 25, 1984 (argued February 29, 1984). Opinion of the Court: John Paul Stevens → go there Overruled by Loper Bright Enterprises v. Raimondo (2024) → go there Topic: Administrative law. Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984), was a landmark decision of the Supreme Court of the United States that set forth the legal test used when U.S. federal courts must defer to a government agency's interpretation of a law or statute. The decision articulated a doctrine known as "Chevron deference". Chevron deference consisted of a two-part test that was deferential to government agencies: first, whether Congress has spoken directly to the precise issue at question, and second, "whether the agency's answer is based on a permissible construction of the statute". Wiki link