On June 18, 2001, the U.S. Supreme Court decided United States v. Mead Corp.,¹ the third time in the last two years that the Court has directly addressed the question of when the deference authorized by Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc.² applies to federal agency decisions.³ Dissenting, Justice Antonin Scalia said of the majority's opinion: "Its consequences will be enormous, and almost uniformly bad."⁴

Why would the mild mannered Justice write in such harsh terms? The answer may lie in Justice Scalia's view that Chevron had established a regime in which statutory ambiguity gave rise to a presumption "that Congress meant to give the agency discretion, within the limits of reasonable interpretation, as to how the ambiguity is to be resolved. By committing enforcement of the statute to an agency rather than the courts, Congress committed its initial and primary interpretation to that branch as well."⁵ To Justice Scalia, this principle is "important to the division of powers between the Second and Third Branches."⁶