Last week, the Supreme Court decided Mellouli v. Lynch, an immigration adjudication case raisingChevron issues. Chris Walker and Patrick Glen have written excellent posts on the decision here and here, but I thought I would add a few more thoughts. At issue in the case was the BIA’s interpretation of 8 U.S.C. § 1227(a)(2)(B)(i), which authorizes deportation of aliens convicted of a state law offense “relating to a controlled substance (as defined [by federal law]).” The BIA interpreted §1227 to allow removal for an offense involving any controlled substance (not one defined by federal law). The Court refused to defer to the interpretation, saying that the BIA’s interpretation “makes scant sense.” As Walker and Glen have nicely explained, it is not clear whether the Court’s decision is based onChevron step 1 or step 2.

That ambiguity highlights a problem with National Cable & Telecommunications Ass’n v. Brand X Internet Services. Brand X says that, if court interprets a statute that an agency is charged with interpreting, that judicial interpretation does not bind the agency unless the basis for the court’s interpretation is that the statute unambiguously commands that interpretation. If the court’s interpretation is based on its own best reading of an ambiguous statute, the agency may adopt later a different interpretation.

Brand X does not require a court to say explicitly that its interpretation is the only reasonable interpretation. Indeed, it suggests that the court may imply that the statute unambiguously dictates its interpretation—through, for example, the court’s refusal to apply the rule of lenity. Needless to say, it is sometimes difficult to determine whether a court has based its interpretation on the unambiguous language of the statute or on the court’s own best reading of an ambiguous statute—and that problem is more likely to arise when courts obscure their analysis by collapsing the Chevron inquiries into one step.

That brings us back to Mellouli. The Court did not say that the unambiguous language of § 1227 commanded its interpretation. Instead, it offered some reasons why the background of § 1227 supported its interpretation, and it explained why the BIA’s different interpretation “makes scant sense.” Those reasons arguably leave room for different BIA interpretations in the future. On the other hand, as Patrick Glen notes, if the Court did really think that the statute was ambiguous, the correct disposition was to remand to the Board for a new interpretation. But the Court did not do that. Instead, it reversed, stating that § 1227 requires a connection between the state law and the federal drug laws. That disposition suggests that the Court thought the statute is unambiguous.

Agencies should not be forced to guess whether a court’s interpretation is based on the plain language. The interpreting court knows better than anyone else the basis for its decision. A clear statement rule would solve the problem. A court’s interpretation should limit subsequent agency interpretations only if the court explicitly says that the basis for its interpretation is that the statute is unambiguous. Agencies have the primary authority to interpret these statutes, and courts should have to clearly state that they are curtailing that power.