Citizen suits are a powerful engine of the major environmental statutes. For over half a century, Congress has empowered the American people to support environmental enforcement through oft-used citizen suit provisions.^[1] These provisions appear in nearly every major environmental statute, including the Clean Air Act, Clean Water Act, and Endangered Species Act.^[2] In times of political change, citizen plaintiffs have acted as a safeguard against relaxed environmental enforcement.^[3] Indeed, citizen plaintiffs now hope to pick up where the Biden administration left off in enforcing these statutes.^[4]

Citizen suit provisions empower citizen plaintiffs, as “private attorneys general,” to pursue declaratory judgments and injunctions.^[5] Still, some statutes like the Clean Water Act go further, allowing citizen plaintiffs to seek civil penalties payable to the federal treasury.^[6] Characterized as a “public remedy” requiring additional restraints under the constitution, the right to seek civil penalties through citizen suits has become an appealing target for challengers.^[7] Objections to citizen suits under the major environmental statutes are nothing new.^[8] Yet, as executive power is rapidly consolidated and the “unitary executive” theory emboldens an adventurous reading of Article II, citizen suits will increasingly face constitutional scrutiny.

In Port of Tacoma v. Puget Soundkeeper Alliance, the Supreme Court may comment on the constitutionality of citizen suits under the Clean Water Act.^[9] The Court has not yet agreed to hear the case and now awaits briefing from the Office of the Solicitor General.^[10] While Article II is directly raised by amici curiae,^[11] petitioners more subtly imply an Article II violation and generally assert that the Ninth Circuit’s interpretation of the Act’s citizen suit provision raises “serious constitutional concerns.”^[12]

For insight into where cases like Port of Tacoma may lead, an amicus brief filed in the Court last term is informative. In Poe v. Idaho Conservation League, which was denied certiorari,^[13] the Center for Constitutional Responsibility participated as amicus and launched a direct Article II challenge, urging the Court to “constrain private attorneys general under the [Clean Water Act.]”^[14] The Center argued that the Vesting Clause, Take Care Clause, and Appointments Clause of Article II “work together to ensure that the executive authority is not outside the President’s control.”^[15] They further asserted that by allowing citizen plaintiffs to seek civil penalties under the Clean Water Act, the Act “authorizes private citizens to exercise unsupervised executive power contrary to Article II.”^[16] While the brief recognized that citizen plaintiffs may not need to be fully accountable to the President if they have meaningful supervision, it claimed that the Act lacks “any meaningful guardrails to constrain self-appointed private attorneys general.”^[17] Regardless of whether the Court chooses to intervene in Port of Tacoma, the Article II concerns expressed by amici, and earlier by the Center in Poe, may soon find new wind.

For now, the familiar reliance on citizen suits under the Clean Water Act and other environmental statutes will proceed. But the current is shifting. As the limits of executive power bloat, the Court is bound to confront Article II of the Constitution and the President’s proper authority as chief executive.^[18] If the Court blesses a re-envisioning of executive power, the ability to seek civil penalties through citizen suits, already taking water, could go under.

[1] Robin Kundis Craig, Will Separation of Powers Challenges “Take Care” of Environmental Citizen Suits? Article II, Injury-in-Fact, Private “Enforcers,” and Lessons From Qui Tam Litigation, 72 U. Colo. L. Rev. 93, 93 (2001).

[2] See 42 U.S.C. §§ 7401-7671; 33 U.S.C. §§ 1251-1387; 16 U.S.C. §§ 1531-1544; 42 U.S.C. §§ 6901-6992; §§ 9601-9675; 15 U.S.C. §§ 2601-2692; 42 U.S.C. §§ 11001-11050.

[3] David Adelman and Jory Reilly-Diakun, Environmental Citizen Suits and the Inequities of Races to the Top, 92 U. Colo. L. Rev. 377, 379-80 (2021); see Scott Strand, At Risk: Citizen Suits and the Doctrine of Standing, Env’t L. and Pol’y Ctr. (June 21, 2023), https://elpc.org/blog/citizen-suits-and-the-doctrine-of-standing/.

[4] Bina Reddy et al., The Citizens Are Coming: Citizen Groups Are Better Funded Than Ever and Will Take Over Where Biden Left Off, Beveridge & Diamond (Feb. 21, 2025), https://www.bdlaw.com/publications/the-citizens-are-coming-citizens-groups-are-better-funded-than-ever-and-will-take-over-where-biden-left-off/; see Here’s How NRDC is Fighting Back Against the Trump Administration in Court, Nat. Res. Def. Council (Feb. 12, 2025), https://www.nrdc.org/court-battles/how-nrdc-fighting-against-trump-administration.

[5] See Jonathan H. Adler, Stand or Deliver: Citizen Suits, Standing, and Environmental Protection, 12 Duke Env’t L. & Pol’y F. 39, 47 (2001).

[6] See Craig, supra note 1, at 93; see also, e.g., 33 U.S.C. § 1365(a); 33 U.S.C. § 1319(d).

[7]See Brief for Center for Constitutional Responsibility as Amicus Curiae Supporting Petitioner, Poe v. Idaho Conservation League, WL 1741274, at *8 (2024) (No. 23-1028) (citing Friends of the Earth, Inc, v. Laidlaw Env’t Servs., 528 U.S. 167, 204-05 (2000) (Scalia, J., dissenting)).

[8] E.g., Atlantic States Legal Found., Inc. v. Buffalo Envelope, 823 F. Supp. 1065, 1073-75 (W.D.N.Y. 1993); Natural Res. Def. Council, Inc. v. Outboard Marine Corp., 692 F. Supp. 801, 815-17 (N.D. Ill. 1988); Chesapeake Bay Found. v. Bethlehem Steel Corp., 652 F. Supp. 620, 623-26 (D. Md. 1987); William H. Lewis, Jr., Environmentalists’ Authority to Sue Industry for Civil Penalties is Unconstitutional Under the Separation of Powers Doctrine, 16 Envtl. L. Rep. 10101 (1986).

[9] See Petition for Writ of Certiorari, Port of Tacoma v.  Puget Soundkeeper Alliance, WL 4360480, at 3*, 15* (2024) (No. 24-350).

[10] Lesley Clark et al., Supreme Court Rejects Climate, Lands, Wind, Air Battles, E&E News (1/13/2025, 2:02 PM), https://www.eenews.net/articles/supreme-court-rejects-climate-lands-wind-air-battles/.

[11] Brief for the Chamber of Commerce of the United States et al as Amicus Curiae Supporting Petitioners, Port of Tacoma, WL 4640259, at *5, *11-*12 (2024) (No. 24-350).

[12] Petition for Writ of Certiorari, Port of Tacoma, WL 4360480, at *3 (2024) (No. 24-350).

[13] Poe v. Idaho Conservation League, 86 F.4th 1243 (9th Cir.), cert denied, 144 S.Ct. 2717 (mem) (2024).

[14] Brief for Center for Constitutional Responsibility as Amicus Curiae Supporting Petitioner, Poe v. Idaho Conservation League, WL 1741274, at *13 (2024) (No. 23-1028).

[15] Id. at *4.

[16] Id. at *6.

[17] Id. at *9.

[18] See John Kruzel, ‘Unitary Executive’ Theory May Reach Supreme Court as Trump Wields Sweeping Power, Reuters (Feb. 14, 2025), https://www.reuters.com/legal/unitary-executive-theory-may-reach-supreme-court-trump-wields-sweeping-power-2025-02-14/.