Yale Law Journal
Under Marbury v. Madison, it is "emphatically the province and duty of the judicial department to say what the law is." But in the last quarter-century, the Supreme Court has legitimated the executive's power of interpretation, above all in Chevron, U.S.A., Inc. v. Natural Resources Defense Council, the most cited case in modern public law. Chevron is not merely a counter-Marbury for the executive branch, but also the Erie Railroad Co. v. Tompkins of the last half-century. It reflects a salutary appreciation of the fact that the law's meaning is not a "brooding omnipresence in the sky" - and that the executive, with its comparative expertise and accountability, is in the best position to make the judgments of policy and principle on which resolution of statutory ambiguities often depends. The principal qualification has to do with certain sensitive issues, most importantly those involving constitutional rights. When such matters are involved, Congress should be required to speak unambiguously; executive interpretation of statutory ambiguities is not sufficient.
Cass R. Sunstein, "Beyond Marbury: The Exective's Power to Say What the Law is," 115 Yale Law Journal 2580 (2006).