Duke Law Journal

Dueling Canons

Abstract

This Article offers the first targeted study of the Supreme Court’s use of canons and other tools of statutory interpretation in a “dueling” manner—that is, in both the majority and dissenting opinions in the same case, to support opposing outcomes. Taking its inspiration from Karl Llewellyn’s celebrated list of canons and countercanons, this Article examines how often and in what ways the members of the Roberts Court counter each other’s references to particular interpretive tools when disagreeing about the proper reading of a statute. Many of the Article’s findings are unexpected and undermine the assumptions made by some of the most prominent theories of statutory interpretation. Most notably, the data reveal that several of textualism’s most-favored interpretive tools are at least as susceptible to dueling use as the purposivist tools that textualists have long denigrated as indeterminate and readily subject to judicial manipulation. For example, the study shows that the Justices dueled extensively over the meaning of statutory text. By contrast, they dueled at far lower rates over legislative history, purpose, and intent. Moreover, the Justices dueled over dictionary references, the whole act rule, and language canons at rates that were virtually identical to the rates at which they dueled over the purposivist-preferred tools. The study also reveals that the canons do not seem capable of constraining the Justices to vote against ideology and that noncanon tools of analysis, including precedent and practical-consequences-based reasoning, lead to higher rates of dueling than do most traditional canons or tools of statutory interpretation. After reporting the data, the Article examines doctrinal patterns in how the Justices duel over individual canons and explores the theoretical implications of the Justices’ dueling canon use.