Vagueness Avoidance

Vagueness avoidance is a powerful tool of judicial construction for constraining the reach of penal statutes. Unlike ordinary constitutional avoidance, which is triggered by ambiguity and seeks to resolve semantic meaning, vagueness avoidance is triggered by vagueness-related indeterminacies that effectively delegate the legislative task of crime definition; such language requires construction to give it legal effect. Because vague statutory language typically has a practically identifiable core, courts may legitimately craft a judicial construction of the text that captures only that core while excising its indeterminate peripheries. Doing so respects the separation of powers, the principle of legality, and the modern methodological commitment to implementing legislative will through statutory construction.Supreme Court case law supports this conception of vagueness avoidance, as the Court has traditionally been explicit about taking that approach with federal penal statutes containing indeterminate language. Yet, in a recent line of cases, the Court has moved toward implicit vagueness avoidance—the practice of justifying narrow constructions of indeterminate penal statutes on the basis of mere interpretation that determines semantic meaning. That practice reflects an unfortunate conflation of vagueness avoidance and ordinary constitutional avoidance.The practical effect is that the Court’s recent decisions rejecting exceedingly broad lower-court readings of penal statutes do little to deter lower courts from adopting similarly broad constructions in other contexts. Each decision is essentially ad hoc, providing no broadly applicable principles of construction. That emboldens prosecutors to continue exploiting indeterminate language in the federal criminal code to attach criminal penalties to a wide range of commonplace conduct.The Court should change course by explicating vagueness avoidance as a distinct and robust rule of construction. When applying vagueness avoidance, the Court should clearly identify the core-penumbra framework exhibited by the vague term and excise the indeterminate penumbra from the core. Adherence to that approach would provide a ready tool of construction that can be used to reduce the breadth and imprecision of penal statutes