Bibb Balancing

60 Pages Posted: 1 Aug 2022 Last revised: 29 Oct 2022

See all articles by Michael S. Knoll

Michael S. Knoll

University of Pennsylvania Carey Law School; University of Pennsylvania Wharton School -- Real Estate Department

Ruth Mason

University of Virginia School of Law

Date Written: August 1, 2022


Courts and commentators have long understood dormant Commerce Clause doctrine to contain two types of cases: discrimination and undue burdens. This Article argues for a more nuanced understanding that divides undue burdens into single-state burdens—which arise from the application of a single state’s law alone—and mismatch burdens, which arise from legal diversity. Although the Supreme Court purports to apply Pike balancing in all undue-burden cases, we show that the Court’s approach in mismatch cases differs substantially. Specifically, unlike in single-state cases, balancing in mismatch cases involves an implicit and potentially problematic comparison by the Court between the challenged state’s regulation and those of other states. We label analysis in mismatch cases “Bibb balancing,” after the famous mudflaps case, and we show that mismatch cases present the Court with a more challenging set of issues than do other types of dormant Commerce Clause cases. Despite the criticisms that attach to Bibb balancing, we recognize that failing to restrain regulatory mismatches would threaten the smooth functioning of the national marketplace and undercut important federalism values. Thus, in addition to clarifying the doctrine and acknowledging the drawbacks of Bibb balancing, this Article provides advice for achieving more consistent and defensible results in mismatch cases.

Keywords: dormant Commerce Clause, Pike balancing, legal mismatches, federalism, horizontal federalism, balkanization

JEL Classification: H71, K34

Suggested Citation

Knoll, Michael S. and Mason, Ruth, Bibb Balancing (August 1, 2022). George Washington Law Review, Vol. 91, No. 1, 2023 (forthcoming), U of Penn, Inst for Law & Econ Research Paper No. 22-30, Virginia Public Law and Legal Theory Research Paper No. 2022-52, Available at SSRN:

Michael S. Knoll

University of Pennsylvania Carey Law School ( email )

3501 Sansom Street
Philadelphia, PA 19104
United States
215-898-6190 (Phone)
215-573-2025 (Fax)

University of Pennsylvania Wharton School -- Real Estate Department ( email )

Philadelphia, PA 19104-6330
United States

Ruth Mason (Contact Author)

University of Virginia School of Law ( email )

United States

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