Litigating EPA Rules: A Fifty-Year Retrospective of Environmental Rulemaking in the Courts

32 Pages Posted: 16 Oct 2020 Last revised: 16 Mar 2021

See all articles by Cary Coglianese

Cary Coglianese

University of Pennsylvania Law School

Daniel Walters

The Pennsylvania State University (University Park) – Penn State Law

Date Written: 2020


Over the last fifty years, the U.S. Environmental Protection Agency (EPA) has found itself repeatedly defending its regulations before federal judges. The agency’s engagement with the federal judiciary has resulted in prominent Supreme Court decisions, such as Chevron v. NRDC and Massachusetts v. EPA, which have left a lasting imprint on federal administrative law. Such prominent litigation has also fostered, for many observers, a longstanding impression of an agency besieged by litigation. In particular, many lawyers and scholars have long believed that unhappy businesses or environmental groups challenge nearly every EPA rule in court. Although some empirical studies have questioned this prevailing belief, no one has yet provided a comprehensive account of litigation challenging EPA rules throughout the agency’s entire history. In this article, we first synthesize the existing disparate empirical studies, each drawn from different time periods, to show how collectively this research creates a picture in stark contrast with prevailing impressions of an EPA besieged by litigation. We also bring new data to bear, providing the first comprehensive empirical effort to track, across the last half-century, both levels of EPA rulemakings and court decisions involving the agency. What we find confirms previous studies in challenging conventional wisdom. EPA has incurred a fairly modest rate of judicial review and invalidation of its rules. Moreover, the variation we do observe over time occurs within a relatively small band, suggesting more continuity than change in litigation patterns over time. The agency appears, from its earliest days, to have quickly achieved a kind of equilibrium in its relationship with the courts. We conclude by suggesting that this outcome would be expected from professional staff efforts within EPA to adapt to changes in the legal environment so as to manage litigation risk and insulate the agency from much judicial scrutiny.

Keywords: Administrative law, environmental regulation, empirical legal studies, judicial review, litigation, Environmental Protection Agency, EPA, rule challenges, agency deference, scrutiny, Supreme Court, Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc.

Suggested Citation

Coglianese, Cary and Walters, Daniel, Litigating EPA Rules: A Fifty-Year Retrospective of Environmental Rulemaking in the Courts (2020). Case Western Reserve Law Review, Vol. 70, p. 1007, 2020, U of Penn Law School, Public Law Research Paper No. 20-35, Penn State Law Research Paper No. 19-2020, Available at SSRN:

Cary Coglianese (Contact Author)

University of Pennsylvania Law School ( email )

3501 Sansom Street
Philadelphia, PA 19104
United States
215-898-6867 (Phone)


Daniel Walters

The Pennsylvania State University (University Park) – Penn State Law ( email )

Lewis Katz Building
University Park, PA 16802
United States

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