Abbe R. Gluck (Yale University – Law School) has posted The End of Ambiguity (in Statutory Interpretation) (forthcoming Duke L.J. (2026)) on SSRN. Here is the abstract:
This article is the first to chart the demise of ambiguity as the key doctrinal trigger across statutory interpretation. So doing is an essential exercise in understanding the modern view of Article III and the judicial role when it comes to statutory work. As the role of ambiguity declines, we move from a framework of faithful agency by judges to Congress to an era in which the judiciary instead lacks no confidence about its own interpretive authority and is happy to act alone.
A finding of ambiguity has long opened the door to hundreds of interpretive tools—not only to widely known doctrines like administrative deference, but also to virtually every tool of interpretation, from legislative history to the application of the more than 100 substantive (policy-or-constitutional-law-based) canons like constitutional avoidance, and even to drier presumptions about grammar and linguistic meaning. Today, however, after more than a century at the fulcrum of statutory interpretation, the ambiguity threshold is vanishing from its doctrine. In many cases, oft-deployed canons ranging from constitutionally-inspired presumptions like federalism and the major questions rule to linguistic assumptions like ejusdem generis to remedial presumptions like severability, are now the starting point for a statutory inquiry, rather than a tiebreaker when other inquiries fail. These old rules are being refashioned to shape textual meaning, even when the Court admits that the text itself, without applying those rules, has a different, more plausible, natural reading.
In other cases, the ambiguity threshold for particular canons is being raised so high that it seems some judges are trying to eliminate use of that canon entirely—a debate currently playing out over the rule of lenity. And in still other cases, the very fact that certain canons still depend on an ambiguity threshold, for example the Indian canon, has made those same canons targets for possible elimination. Together, these moves appear to be creating an unprecedented hierarchy of interpretive rules.
The path to ambiguity’s imminent demise is being paved by few factors. First, is the enduring frustration about the manipulability of any ambiguity threshold. Second, there is a growing jurisprudential discomfort with the substantive canons in general, and from where courts draw the authority to create and apply these policy norms atop Congress’s work. Justice Barrett’s scholarship was highly critical of the canons’ jurisprudential foundations, and Justices Kagan, Gorsuch, Alito, and Kavanaugh all have raised questions about what makes the canons legitimate. Third, this Court lacks the inferiority complex of its predecessors. Federal courts for decades have articulated concerns about their role in interpreting statutes under the umbrella of legislative supremacy. These concerns long expressed themselves in interpretive doctrine. But this Court—the second-generation textualists—has argued that courts should care much less about Congress, and focus instead on the “ordinary reader.” This new focus—and with it a growing lack of interest in whether Congress has delegated any interpretive space to courts (via ambiguity)—has combined with long-standing critiques of the construct to create momentum for toppling the ambiguity-based pyramid altogether.
Ultimately, the shift away from ambiguity is about Article III and judicial power. A court that requires ambiguity as evidence of delegation of interpretive authority has a different conception of its own constitutional power than a court that thinks it can apply its policy preferences atop Congress’s work, even if the text does not naturally permit it. It is long past time that the Court acknowledge this shift and justify it as a matter of the Court’s lawmaking authority. While the Court rarely engages openly with the jurisprudential underpinnings of the rules of interpretation and what triggers them, those questions go to the heart of any conception of judicial power under Article III and the judiciary’s relation to the other branches in our constitutional structure.
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