Supreme Court Report

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Kentucky, et al. v. Environmental Protection Agency, et al.

Paid petition · United States Court of Appeals for the District of Columbia Circuit, No. 24-1050, 24-1051, 24-1052, 24-1073, 24-1091 · judgment June 26, 2026


44%
estimated cert probability
(petition-stage, structural)
95% interval 33%–55%
Rule 10: dissent below, circuit split argued

About 10.6× the 4.1% base rate. The model weights this up for counsel who has won certiorari before, a D.C. Circuit decision below, and a petition filed soon after the judgment below.

Questions presented

The Clean Air Act allows the Environmental Protection Agency (EPA) to revise a national ambient air quality standard (NAAQS) only after a “thorough review” of its air-quality criteria and the current standard. 42 U.S.C. § 7409(d)(1). But in 2024, EPA used a short-circuited reconsideration process—involving an intentionally narrow review of a few limited studies— to revise the air-quality standards for fine particulate matter (PM2.5) to the most restrictive level ever. Although EPA later disavowed any power to revise NAAQS without a thorough review, the D.C. Circuit rejected that concession and approved an expansive view of EPA’s authority anyway. The questions presented are:

  1. Whether the Clean Air Act gives EPA the authority to revise NAAQS without conducting a thorough review merely because the revision occurs before the normal, five-year review.

  2. Whether the Clean Air Act bars EPA from considering the costs and feasibility of revising NAAQS when deciding whether to exercise its discretion to undertake a revision before the normal, five-year review.

Counsel of record

For petitioner
Matthew Franklin Kuhn
Office of Attorney General of Kentucky

For respondent
D. John Sauer
Solicitor General

Case

Conference history

Proceedings

  1. Aug 28 2026
    Petition for a writ of certiorari filed. (Response due October 2, 2026)