Fishing businesses challenged a federal rule requiring industry-funded monitors and asked the courts to reject Chevron deference to the agency’s statutory interpretation. The Supreme Court overruled Chevron U.S.A. Inc. v. Natural Resources Defense Council. It held that the Administrative Procedure Act requires courts to exercise independent judgment in deciding whether an agency acted within its statutory authority. Agency expertise and longstanding interpretations may deserve respectful consideration, and Congress may expressly delegate discretionary authority, but statutory ambiguity alone does not transfer interpretive power from judges to agencies. The judgments were vacated and the cases remanded under the independent-judgment standard.