Both the Chevron doctrine and West Virginia v. EPA are based on ideas about the delegation of interpretive authority from Congress to administrative agencies. Chevron introduced the idea of "implicit" delegations, and the doctrine spawned by it eventually held that any ambiguity in an agency statute is an implicit delegation. West Virginia is effectively an unacknowledged carveout. Without the majority's mentioning Chevron, the case posits that when a "major question" is involved, a delegation must take the form of a clear statement; presumably, only express delegations or something close to this will count.
Both positions are extreme. The idea that any ambiguity is a delegation transfers too much power to the administrative state. The view that only express delegations will do for major questions concentrates too much power in reviewing courts.
The better position, as suggested in my recent book, The Chevron Doctrine: Its Rise and Fall, and the Future of the Administrative State (Harvard University Press 2022), is that courts should condition any strong form of deference to agency interpretations on a finding that Congress has actually delegated authority to the agency to resolve the issue. This means more than finding ambiguity; courts must carefully interpret the statute and conclude that Congress left a gap for the agency to fill.
