Prominent judges and scholars have criticized the familiar Chevron deference scheme on the ground that its two steps are redundant. But each step of traditional two-step Chevron actually does unique interpretive work. In short, step one asks whether agency interpretations are mandatory, whereas step two asks whether they are reasonable. Other judges and scholars defend two-step Chevron on the ground that the second step should be equated with arbitrary-and-capricious review. But that approach makes Chevron partially redundant with the Administrative Procedure Act and compresses the distinct mandatoriness and reasonableness questions into an artificially singular first step. This Article identifies a new approach, called “optional two-step,” which first asks whether the agency’s view is reasonable and then gives courts discretion to determine whether the agency’s view is also mandatory. This discretionary decision procedure recognizes that important normative considerations underlie the choice between one- and two-step versions of Chevron. For example, two-step Chevron fosters the rapid development of precedent, whereas one-step enforces norms of judicial restraint. Chevron thus resembles qualified-immunity jurisprudence, which has likewise struggled to answer the normative question of whether unnecessary holdings should be impermissible, obligatory, or optional. Qualified-immunity case law also sheds much-needed light on how courts should exercise their Chevron discretion. Finally, a review of all published federal appellate decisions citing Chevron in 2011 sheds light on current Chevron practice and suggests that optional two-step may best explain the tensions underlying current Chevron jurisprudence
