*Isabelle Pardew
- Introduction
On February 13, 2026, the National Association for the Advancement of Colored People (NAACP) filed a sixty-day notice of intent to sue X.AI Corp. (xAI) and its subsidiary MZX Tech for violations of the Clean Air Act (CAA).[1] The NAACP alleged that xAI installed twenty-seven combustion turbines for a planned data center in Memphis, Tennessee, without the permits required by the CAA.[2] On April 14, 2026, after xAI took no action to curtail data center operations, the NAACP filed suit.[3] The NAACP brought its action under the CAA’s citizen suit provision, which enables private citizens or organizations to file suit in federal court to enforce the CAA where government enforcement is lacking.[4] Under the CAA, the government may still pursue its own action or intervene in the ongoing citizen suit.[5]
The case’s most notable development occurred on June 15, 2026, when the Department of Justice (DOJ) moved to intervene and dismiss the action pursuant to its asserted authority under Article II of the United States Constitution.[6] In September 2026, the DOJ filed a notice of appeal and moved to stay the proceedings pending review of its motion to intervene and dismiss.[7]
Thus, while the original dispute centered on alleged CAA permitting violations, NAACP v. X.AI Corp. presents the broader question of whether the Constitution provides the Executive ultimate control over federal enforcement despite congressional authorization of private actions.[8]
- The Citizen Suit Provision
The CAA is among several federal environmental statutes that permit private plaintiffs, under statutorily defined circumstances, to bring civil actions against alleged violators rather than solely relying on government enforcement.[9] The precise requirements vary by statute, but generally citizen suit plaintiffs must satisfy procedural prerequisites, such as pre-suit notice and demonstration of an ongoing or continuing violation.[10] Citizen enforcement may not proceed if the government is already actively prosecuting the same violation.[11] Despite legislative and judicial limitations that have diminished their potency, citizen suits remain a key component of modern environmental law, supplementing government enforcement and enabling private participation within boundaries expressly established by Congress.[12]
- Article II’s Absorption of “Citizen” Enforcers
- Moving Beyond Enforcement Discretion Toward Dismissal Authority
The DOJ’s motion to intervene and dismiss the case presents a novel assertion of executive power.[13] The DOJ grounds its authority to intervene and dismiss in the Federal Rules of Civil Procedure and the Executive’s inherent Article II powers.[14] As to the former, the DOJ’s amended motion emphasizes Rule 41 as an independent basis for dismissal.[15] Separately, the DOJ argues that Article II provides the Executive with authority to assume control over citizen suit litigation when private enforcement conflicts with federal policy or the Executive’s decision not to enforce.[16] The DOJ further contends that the NAACP’s claims threaten national security because the private enforcement action seeks to eliminate “the power supply for artificial-intelligence innovation that supports the Department of War’s military operations.”[17]
More broadly, the DOJ invokes Article II as authority to assume control over enforcement where “a citizen’s attempted civil enforcement action is inconsistent with federal policy and the public interest,” including where the Executive deliberately chose not to pursue enforcement.[18] Significantly, the DOJ asserts that citizen suits are unconstitutional or, alternatively, that the CAA authorizes citizen suits only with the government’s consent.[19] The DOJ also contends that the NAACP’s request for civil penalties, payable to the Treasury, seeks relief that closely resembles an enforcement action brought by the government and “bears only the most attenuated relationship, if any, to the plaintiff’s own asserted injuries.”[20]
The DOJ does not dispute Congress’s authority to create private causes of action, including those under the Civil Rights Act or the Clayton Act.[21] Instead, its constitutional objection focuses on citizen plaintiffs seeking generalized enforcement relief on behalf of the public rather than compensatory monetary relief, which the DOJ characterizes as an exercise of “quintessentially executive power.”[22] In developing its argument, the DOJ relies on dissenting opinions and attempts to distinguish majority precedent recognizing private enforcement.[23]
- Constitutional Challenges to Citizen Suit Provisions
Citizen suit provisions have historically faced constitutional challenges under both Article II and Article III, including arguments that private enforcement impermissibly encroaches upon the Executive’s authority to enforce the law.[24] NAACP v. X.AI Corp. elevates the tension between the Executive’s Article II authority over enforcement of federal law and congressional authority to create private causes of action.[25]
The Supreme Court has yet to definitively resolve the constitutionality of citizen suit provisions, and lower courts have regarded such constitutional challenges with mixed results.[26] The DOJ now advances a broader concept of Article II authority, where the Executive is empowered to intervene and terminate a private action that Congress has expressly authorized but the government elected not to pursue.[27] If accepted, this theory would extend enforcement discretion beyond an affirmative decision to prosecute and instead impede, or eliminate altogether, independently authorized citizen suits.[28]
- Conclusion
Citizen suit provisions reflect Congress’s decision to permit private participation in the enforcement of environmental laws and other statutory schemes.[29] Yet if the DOJ succeeds in both intervention and dismissal, the availability of citizen enforcement may depend entirely on Executive judgment.[30] NAACP v. X.AI Corp. therefore implicates more than just compliance with the CAA.[31] This case foreshadows the simmering question of whether citizens may invoke congressionally created enforcement mechanisms to address environmental and public health concerns when regulators do not act, or whether the Executive ultimately retains unilateral authority to prevent those actions from proceeding.[32]
*Isabelle Pardew is a second-year part-time day student at the University of Baltimore School of Law and a Staff Editor for Volume 56 of the University of Baltimore Law Review. Isabelle is a Law Scholar for Civil Procedure I and Secretary of the Environmental Law Society. Prior to law school, she earned master’s degrees in both mathematics and communication. She works with a climate education nonprofit and manages environmental advocacy initiatives focused on modern infrastructure and its impact on migratory wildlife. In summer 2026, Isabelle was a judicial intern for the Honorable Dan Friedman at the Appellate Court of Maryland. In her free time, she enjoys spending time with her family, reading, and doing crossword puzzles.
[1] Compl. at 4, National Ass’n for the Advancement of Colored People v. X.AI Corp., No. 3:26CV00074 (D. Miss. Apr. 14, 2026).
[2] Id. at 2.
[3] Id. at 1.
[4] See Compl., supra note 1, at 18–19; Roger A. Greenbaum & Anne S. Peterson, The Clean Air Act Amendments of 1990: Citizen Suits and How They Work, 2 Fordham Env’t. Rep. 79, 79 (1991).
[5] Jeffrey G. Miller & Brooke S. Dorner, The Constitutionality of Citizen Suit Provisions in Federal Environmental Statutes, 27 J. Envtl. L. & Litig. 401, 454 (2012).
[6] Memorandum in Support of the United States’ Motion for Intervention and Dismissal at 1, 8, National Ass’n for the Advancement of Colored People v. X.AI Corp., No. 3:26CV00074 (D. Miss. June 15, 2026).
[7] Notice of Appeal at 1, National Ass’n for the Advancement of Colored People v. X.AI Corp., No. 3:26CV00074 (D. Miss. Sept. 18, 2026); Motion to Stay All Proc. Pending Appeal at 1, National Ass’n for the Advancement of Colored People v. X.AI Corp., No. 3:26CV00074 (D. Miss. Sept. 21, 2026).
[8] See discussion infra Part III.
[9] David E. Adelman & Robert L. Glicksman, Reevaluating Environmental Citizen Suits in Theory and Practice, 91 U. Colo. L. Rev. 385, 394 (2020).
[10] Greenbaum & Peterson, supra note 4, at 82, 84.
[11] Miller & Dorner, supra note 5, at 454.
[12] Lia Cattaneo, Wrinkling Citizen Suits: California v. EPA (9th Cir. 2020) and Clean Air Act Underenforcement, 45 Harv. Env’t. L. Rev. 503, 506–08 (2021).
[13] See discussion infra Part III.B.
[14] Memorandum in Support of the United States’ Motion for Intervention and Dismissal, supra note 6, at 1–2; Reply Memorandum in Support of the United States’ Amended Motion for Intervention and Dismissal at 1, 16, National Ass’n for the Advancement of Colored People v. X.AI Corp., No. 3:26CV00074 (D. Miss. July 24, 2026).
[15] Memorandum in Support of the United States’ Motion for Intervention and Dismissal, supra note 6, at 9; Reply Memorandum in Support of the United States’ Amended Motion for Intervention and Dismissal, supra note 14, at 16.
[16] Memorandum in Support of the United States’ Motion for Intervention and Dismissal, supra note 6, at 10.
[17] Id. at 1.
[18] Id. at 8, 10, 12.
[19] Id. at 11.
[20] Id. at 19.
[21] Id. at 23; Civil Rights Act of 1871, 42 U.S.C. § 1983 (2012) (providing that parties subject to a violation of federally-protected civil rights can sue for damages, an injunction, or declaratory relief); Clayton Antitrust Act, 15 U.S.C. §§ 15, 26 (2012) (providing that parties harmed in business or property by antitrust violations can sue for private enforcement and injunctive relief).
[22] Memorandum in Support of the United States’ Motion for Intervention and Dismissal, supra note 6, at 23; Adelman & Glicksman, supra note 9, at 387 (discussing critics’ argument that citizen-suit provisions allow independent environmental organizations to exploit the legal system for their own “extreme ends” and disrupt the regulatory balance struck by more knowledgeable federal agencies).
[23] For example, DOJ invokes Gwaltney of Smithfield, Ltd. v. Chesapeake Bay Found., Inc., 484 U.S. 49 (1987) to suggest that the U.S. Supreme Court has already foreshadowed the precarious constitutionality of citizen suit provisions that interfere with Government enforcement discretion. But Gwaltney dealt solely with past violations, holding them beyond the reach of citizen suits. Rather than establishing authority to extinguish an otherwise permissible citizen suit, Gwaltney defined the statutory limits that Congress itself placed on citizen enforcement.
[24] Cattaneo, supra note 12, at 518–20; Stephen M. Johnson, Private Plaintiffs, Public Rights: Article II and Environmental Citizen Suits, 49 U. Kan. L. Rev. 383, 383–85 (2001).
[25] See discussion supra Part III.A.
[26] In Steel Co. v. Citizens For A Better Env’t, Justice Stevens observed in concurrence that “it is hard to see . . . how the EPCRA’s citizen-suit provision impinges on the power of the executive,” potentially indicating the highest court’s view on the provisions. 523 U.S. 83, 129 (1998) (Stevens, J., concurring). Steel Co. ultimately resolved the case on Article III standing grounds and therefore did not reach the question of whether citizen suits allow for the enforcement of purely historical violations. Justice Stevens’s concurrence nevertheless demonstrates that the potential tension between citizen enforcement and executive authority has reached the Court long before the more direct challenge presented today. More recently, in 2025, the Court declined to hear challenges concerning available remedies in citizen-suit actions, leaving the lower court decisions, and the challenged applications of citizen-suit authority, undisturbed for the moment.
[27] See Memorandum in Support of the United States’ Motion for Intervention and Dismissal, supra note 6, at 18.
[28] See id.
[29] See Miller & Dorner, supra note 5, at 458; Kristi M. Smith, Who’s Suing Whom: A Comparison of Government and Citizen Suit Environmental Enforcement Actions Brought Under EPA-Administered Statutes, 1995-2000, 29 Colum. J. Envtl. L. 359, 363 (2004).
[30] See discussion supra Part III; Memorandum in Support of the United States’ Motion for Intervention and Dismissal, supra note 6, at 11–12.
[31] See discussion supra Part III.B.
[32] See discussion supra Part III.
