摘要:The Supreme Court says that Chevron has two steps: Is the statute ambiguous (Step One), and, if so, is the agency's interpretation of the ambiguous provision a permissible one (Step Two)? Yet over the last three decades, the DC Circuit has inserted an intermediate step between Steps One and Two: Did the agency recognize that the statutory provision is ambiguous? If not, then the DC Circuit refuses to proceed to Chevron Step Two and remands the matter to the agency. This doctrine- which we dub "Chevron Step One-and-a-Half"-has led to dozens of agency losses in the DC Circuit and DC federal district court, but it has gone entirely unmentioned in administrative law casebooks and is rarely referenced in the academic literature. The few who have not ignored the doctrine have treated it with skepticism. Chief among those skeptics is now-Chief Justice John Roberts, who while a DC Circuit judge criticized his colleagues for applying the doctrine. This Article presents a more sympathetic account of Chevron Step One-and-a- Half. After providing an overview of the Chevron Step One-and-a-Half doctrine, we offer several theories why Chevron Step One-and-a-Half cases continue to arise, even though agencies can avoid the doctrine by stating that they would hew to their view regardless of whether the relevant statutory provision is ambiguous. Some number of Chevron Step One-and-a-Half cases might be explained by the fact that agencies are ignorant of the doctrine or ambivalent about their own policies, but we suggest that there also may be strategic reasons why agency actors might maintain that a statute is unambiguous. For instance, agency lawyers with a preference for a particular reading (or with patrons who have such a preference) might seek to increase influence over policy by declaring that a statute can be interpreted only one way. Alternately, an agency might claim that a statute is unambiguous in order to reduce the probability that the White House's Office of Information and Regulatory Affairs will second-guess the agency's choice. In a similar manner, an agency might attempt to evade political accountability for an unpopular policy by claiming that the choice was compelled by Congress. Finally, an agency might maintain that a statute is unambiguous in order to "lock in" an interpretation so that future administrations cannot undo it. After identifying the potential causes of Chevron Step One-and-a-Half cases, we consider how courts ought to respond to the potential for strategic