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University of Chicago Law Review

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This paper provides the first empirical study of the Roberts Court’s use of substantive canons in its statutory interpretation cases. Based on data from 295 statutory interpretation cases decided by the Roberts Court during its first six-and-a-half terms, the paper argues that much of the conventional wisdom about substantive canons of statutory construction is wrong, or at least overstated with respect to the modern Supreme Court. Substantive canons — such as the rule of lenity, the avoidance canon, or the presumption against extraterritorial application of domestic laws — have long been criticized as undemocratic judge-made rules that defeat congressional intent, afford willful judges a convenient vehicle for massaging different meanings out of the same text, and make statutory interpretation unpredictable, because judges invent new canons and reject old ones to suit their changing tastes. Scholars have bemoaned the amount of work that substantive canons perform in statutory interpretation cases and several have charged that textualist judges, in particular, overuse such canons.

Whereas most previous studies have focused on the Rehnquist Court, this paper reconsiders the substantive canons in light of new data collected from the Roberts Court. The data show that contrary to the conventional wisdom, substantive canons are infrequently invoked on the modern Court — and that, even when invoked, they rarely play an outcome-determinative role in the Court’s statutory constructions. Indeed substantive canons often are referenced as an afterthought, or add-on argument supplying minimal additional support to an interpretation reached primarily through other interpretive tools. Perhaps most surprisingly, textualist Justices rarely invoke substantive canons in the opinions they author; indeed, intentionalist Justice Stevens leads the Roberts Court in references to such canons.

The paper also challenges scholars’ gloomy warnings that Justices in the modern, New-Textualism-influenced era have replaced legislative history with substantive canons as the go-to resource for deciphering ambiguous statutory text. Rather, the data from the Roberts Court show that most of the Justices referenced legislative history at slightly, or even substantially, higher rates than they referenced substantive canons. Moreover, the Court’s own precedents, followed by practical-consequences-based reasoning — rather than substantive canons or legislative history — seem to be the unsung gap-filling mechanisms that the Justices turn to when confronted with unclear statutory text. The paper first reports the findings from my study of 295 Roberts Court cases and then explores the theoretical implications of these findings for several leading statutory interpretation theories and debates.

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