In 2024, the Supreme Court fundamentally reshaped administrative law when it overruled Chevron U.S.A., Inc. v. NRDC, 467 U.S. 837 (1984), ending the longstanding rule requiring courts to defer to reasonable agency interpretations of ambiguous statutes. For decades before that decision, judicial review operated under two related but distinct doctrines. Under Chevron, courts deferred to reasonable agency interpretations of ambiguous statutes, while Skidmore v. Swift & Co., 323 U.S. 134 (1944), recognized agency interpretations as persuasive authority grounded in their reasoning, consistency, and expertise.