University of Chicago Law Review

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This Article provides the first empirical study of the Roberts Court's use of substantive canons in statutory interpretation cases. Based on data from 296 cases, the Article 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-for example, the rule of lenity, the avoidance canon, and the presumption against extraterritorial application of domestic laws- have long been criticized as undemocratic judge-made rules that defeat congressional intent, enable interpreters to massage different meanings out of the same text, and make statutory interpretation unpredictable. 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. But virtually all of these critiques have occurred in the absence of empirical evidence about how judges invoke substantive canons in practice. This Article 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 even when invoked, they rarely play an outcome-determinative role in the Court's statutory constructions. Perhaps most surprisingly, textualist justices-including Justice Antonin Scalia-rarely invoke substantive canons in the opinions they author, and do so less often than most of their purposivist counterparts. Moreover, contrary to the conventional view that substantive canons empower judges to read their personal policy preferences into statutes, the Court's conservative justices have employed substantive canons to support liberal case outcomes as often, or nearly as often, as they have employed such canons to support conservative outcomes. Further, doctrinal analysis shows that the Roberts Court repeatedly has used substantive canons to honor, rather than frustrate, congressional intent. The Article also challenges scholars' gloomy warnings that justices in the modern, 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 higher rates than they referenced substantive canons. More- over, the Court's own precedents-rather than substantive canons or legislative history-seem to be the unsung gap-filling mechanism that the justices turn to when confronted with unclear statutory text. After reporting the data, the Article discusses the implications of its findings for current debates in statutory interpretation, arguing that statutory interpretation theory needs to pay less attention to substantive canons and more attention to how the Court employs precedents when construing statutes.