Law, Equity, and Supplemental Jurisdiction

23 Pages Posted: 25 May 2022 Last revised: 1 Jun 2022

Date Written: May 25, 2022


As remedies scholars continue to reflect on the consequences of the 1938 merger of law and equity into one civil action, it may be worth pondering a second merger. In 1990, responding to a Supreme Court opinion that highlighted the absence of such authority, Congress adopted a statutory framework for the exercise of judge-made doctrines of pendent and ancillary jurisdiction. In the statute, 28 U.S.C. § 1367, Congress merged the two doctrines, lumping them together in a provision for the exercise of supplemental jurisdiction over claims that bear an appropriate relationship to civil actions within the district courts’ original jurisdiction.

This Essay, prepared for a symposium on federal equity, explores some consequences of that jurisdictional merger. We focus on cases in which federal courts have declined to exercise traditional forms of ancillary jurisdiction after concluding that those forms threatened to undermine the complete diversity rule. Thus, in Griffin v. Lee, a 2010 decision, the Fifth Circuit refused to allow the district court to exercise ancillary jurisdiction over a withdrawing lawyer’s claim for attorney’s fees. Although misguided textualism helped, the mistaken decision in Griffin owes much to the court’s failure to appreciate the distinctively equitable underpinnings of ancillary jurisdiction.

Generalizing from its critique of Griffin, the Essay argues that federal courts should attend to the history of ancillary jurisdiction in evaluating the threat to diversity-based jurisdiction under the supplemental jurisdiction statute. For much of the nation’s history, ancillary jurisdiction extended to the related claims of nondiverse claimants (like those of the lawyer in Griffin) that arose in the course of litigation. Reclaiming these equitable traditions will enable courts to return to the discretionary framework Congress provided as the measure of supplemental jurisdiction.

Keywords: law, equity, ancillary jurisdiction, supplemental jurisdiction, textualism

JEL Classification: K10, K30

Suggested Citation

Pfander, James E. and Douglas, Peter C., Law, Equity, and Supplemental Jurisdiction (May 25, 2022). Northwestern Public Law Research Paper No. 22-17, Notre Dame Law Review, Forthcoming, Available at SSRN: or

James E. Pfander (Contact Author)

Northwestern University School of Law ( email )

375 E. Chicago Ave
Chicago, IL 60611
United States

Peter C. Douglas

Northwestern University - Northwestern Pritzker School of Law ( email )

750 N. Lake Shore Drive
Chicago, IL 60611
United States

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