The Chevron standard for judging agency statutory interpretations is ubiquitous in administrative law cases. The prototypical Chevron case arises where an agency has promulgated a regulation that takes a particular view of the authorizing statute, and the regulation is then challenged as inconsistent with the statute. At that point, the court is supposed to ask first, whether “Congress has directly spoken to the precise question at issue” and if so, whether the regulation is consistent with the clear meaning of the statute. If the “statute is silent or ambiguous with respect to the specific issue, [then] the question for the court is whether the agency’s answer is based on a permissible construction of the statute.” ...