Splitting the Statute: Severability as a Canon of Construction or Constitutional Concern?

Authors

Amy L. Moore

Abstract

Severability doctrine stands at the crossroads of statutory interpretation and constitutional structure. This Article traces how the Supreme Court has struggled to define whether severability is merely an interpretive presumption designed to preserve as much of Congress’ work as possible, or a constitutional limit on judicial power that forbids courts from reconstructing statutes Congress never enacted. Beginning with Marbury v. Madison and running through cases like Alaska Airlines, Booker, Ayotte, Seila Law, and Loper Bright, this Article charts the Court’s shifting rationales from legislative intent and functional operability to structural separation-of-powers concerns. It distinguishes between textual severability, where courts decide whether invalid provisions can be excised while leaving the remainder intact, and application severability, where a statute is valid on its face but unconstitutional in certain applications. In examining more recent cases, this Article argues that the Court’s severability analysis now serves as a barometer of judicial restraint: expansive in preserving landmark legislation, but skeptical when agency power is at stake. The result is a doctrine that both preserves and constrains the administrative state and large legislation, revealing severability’s dual identity as a canon of construction and a constitutional boundary on judicial lawmaking.

Recommended Citation

Amy L. Moore, Splitting the Statute: Severability as a Canon of Construction or Constitutional Concern?, 75 Cath. U. L. Rev. 50 (2025).
Available at: https://scholarship.law.edu/lawreview/vol75/iss1/7