Amicus Curiae Cannot Appeal Without Rule 24 Intervention: Sixth Circuit Reaffirms Party-Only Appellate Jurisdiction

1. Introduction

United States v. State of Michigan (6th Cir. Mar. 11, 2025) addresses a recurring procedural problem in complex, long-running public-law decrees: when an organization participates as amicus curiae—even actively, even for decades—can it appeal an adverse decree without first becoming a party?

The underlying dispute concerns the allocation, management, and regulation of fishing in Great Lakes waters through a successor consent decree, the 2023 Great Lakes Fishing Decree (“2023 Decree”). The “Stipulating Parties” (the United States, the State of Michigan, and several Tribes) negotiated and proposed the decree. The Coalition to Protect Michigan Resources (“Coalition”), a nonprofit representing recreational fishing and conservation interests, participated only as amicus curiae and filed extensive objections. The district court overruled those objections and entered the 2023 Decree, while also suggesting the Coalition could appeal.

The key issue on appeal was not the merits of fisheries management or treaty fishing rights; it was jurisdictional: Does the Sixth Circuit have appellate jurisdiction over an appeal filed by an amicus that never intervened?

2. Summary of the Opinion

The Sixth Circuit dismissed the Coalition’s appeal for lack of appellate jurisdiction because the Coalition “only appears as amicus curiae and was never granted party status through intervention.” It also dismissed as moot the United States’s cross-appeal challenging the Coalition’s claimed right to appeal.

The court reaffirmed a bright-line principle: generally, only parties may appeal, and a non-party becomes a party for appellate purposes by intervening under Federal Rule of Civil Procedure 24. The Coalition never filed a motion to intervene in connection with the entry of the 2023 Decree and therefore could not appeal it—regardless of how fully it participated as an amicus in objecting to the decree.

3. Analysis

3.1 Precedents Cited

The opinion is primarily a jurisdiction-and-procedure decision, built from Supreme Court authority and the Sixth Circuit’s prior management of this same institutional litigation. The cited cases collectively establish (i) the party-only nature of appellate standing, (ii) intervention as the required gateway for non-parties, (iii) narrow exceptions, and (iv) limits on “litigating amicus” practices.

  • Marino v. Ortiz, 484 U.S. 301 (1988)
    This is the opinion’s anchor. Marino held that non-parties who did not intervene “may not appeal from” a consent decree. The Sixth Circuit uses Marino to reject the Coalition’s attempt to convert robust participation (objections, argument) into appellate rights. The opinion also echoes Marino’s admonition that the “better practice” is to intervene “for purposes of appeal.”
  • Bender v. Williamsport Area School District, 475 U.S. 534 (1986)
    Bender supplies the formalism of Rule 24: a would-be appellant must make a “timely application” by “appropriate motion” stating grounds and pleading the claim/defense for which intervention is sought. The court analogizes the Coalition’s failure to file any intervention motion to the defect in Bender that deprived the appellate court of jurisdiction.
  • Stringfellow v. Concerned Neighbors in Action, 480 U.S. 370 (1987)
    Cited for the standard proposition that a non-party may become a party for purposes of appeal through intervention. It functions as doctrinal connective tissue: Rule 24 intervention is the recognized path from non-party to appellant.
  • City of Cleveland v. Ohio, 508 F.3d 827 (6th Cir. 2007)
    The Coalition relied on City of Cleveland for the idea that “de facto parties” may appeal without formal intervention. The Sixth Circuit distinguishes it: Cleveland “actually was a party,” and it was treated as a de facto party to a third-party claim arising from its conduct—“[i]f it were not for the City, there would be no controversy.” By contrast, the Coalition “was never a party to the action at all,” and the district court repeatedly confined it to a “traditional amicus” role. The decision thereby narrows any temptation to read City of Cleveland as a broad escape hatch from Rule 24.
  • Devlin v. Scardelletti, 536 U.S. 1 (2002) and U.S. ex rel. Eisenstein v. City of New York, 556 U.S. 928 (2009)
    The Coalition invoked Devlin, where nonnamed members of a mandatory Rule 23(b)(1) class could appeal a settlement approval without intervening. The Sixth Circuit rejects the analogy, relying on Eisenstein’s limitation of Devlin to the “class-action nature of the suit.” The court further stresses Devlin’s key rationale—objectors were “bound by the settlement”—which does not apply because the 2023 Decree binds sovereign parties (United States, Michigan, Tribes), not members of the public who fish under state-law terms.
  • Hispanic Society of New York City Police Department Inc. v. New York City Police Department, 806 F.2d 1147 (2d Cir. 1986), aff'd sub nom. Marino v. Ortiz, 484 U.S. 301 (1988)
    This case rebuts the Coalition’s “we objected, we argued, therefore we can appeal” theory. As in Hispanic Society, the would-be appellants filed written objections and argued them at a hearing, but remained non-parties and could not appeal. The Sixth Circuit treats this as directly analogous to the Coalition’s posture.
  • United States v. Michigan, 940 F.2d 143 (6th Cir. 1991)
    This earlier phase of the same mega-litigation supplies the Sixth Circuit’s institutional warning against a “litigating amicus curiae.” The 2025 panel quotes its admonition that amici cannot be “conferred with the authority of an intervening party of right without complying with” Rule 24(a), and cautions that the Federal Rules should not be evaded by “judicial legerdemain.” This is crucial: it frames the present decision as continuity—refusing again to expand amicus practice into functional partyhood.
  • United States v. Michigan, 68 F.4th 1021 (6th Cir. 2023) and United States v. Michigan, 424 F.3d 438 (6th Cir. 2005)
    These cases supply (i) the Coalition’s repeated unsuccessful intervention history and (ii) the four-factor test for intervention as of right. The 2025 opinion uses the 2023 decision to reject the Coalition’s claim that the Sixth Circuit “impliedly instructed” the district court to allow an appeal without intervention. The panel characterizes the prior language as an invitation to “request intervention” later—i.e., to file a proper Rule 24 motion—not as a waiver of Rule 24.
  • Grubbs v. Norris, 870 F.2d 343 (6th Cir. 1989), Buck v. Gordon, 959 F.3d 219 (6th Cir. 2020), and Fed. R. Civ. P. 24(b)
    These authorities set out the elements and burdens for intervention as of right (timeliness, substantial legal interest, impairment, inadequate representation) and permissive intervention (timeliness plus a claim/defense with common questions; plus no undue delay or prejudice). They underscore that intervention is structured and conditional, not an ad hoc reward for participation.
  • Donaldson v. Lyon, 2021 WL 1625413 (6th Cir. Feb. 16, 2021)
    Used as a recent example that the Sixth Circuit dismisses appeals when appellants never “became a party or an intervenor.” It reinforces that the holding is not limited to consent decrees or special contexts.
  • In re Associated Press, 162 F.3d 503 (7th Cir. 1998) and City of Cleveland v. Ohio, 508 F.3d 827 (6th Cir. 2007) (on scope of appeal after denial of intervention)
    These cases support the rule that someone who unsuccessfully seeks intervention may appeal only the denial of intervention—not the merits of the underlying judgment. This highlights the procedural path the Coalition could have taken: file a motion; if denied, appeal that denial.
  • Broidy Cap. Mgmt. LLC v. Muzin, 61 F.4th 984 (D.C. Cir. 2023)
    Cited for the normative justification: party-only appellate rules are not “mere technicalit[ies]” but provide structure “essential to the administration of justice.” This frames the decision as protecting institutional order in complex litigation.

3.2 Legal Reasoning

The court’s reasoning proceeds in a strict jurisdictional sequence:

  1. Appellate jurisdiction is limited to parties (and properly admitted intervenors).
    The panel begins with the general rule from Marino v. Ortiz and the intervention pathway described in Stringfellow.
  2. Rule 24 is the gatekeeper; participation as amicus is not a substitute.
    The Coalition never filed a Rule 24 motion connected to the 2023 Decree’s entry. Under Bender v. Williamsport Area School District, that omission is dispositive: without a motion and pleading, the appellate court lacks jurisdiction.
  3. “De facto party” theory does not fit the facts.
    The Coalition attempted to analogize itself to the City in City of Cleveland v. Ohio. The panel rejects this by focusing on role and causation: the City was an actual party whose actions generated the controversy; the Coalition remained an amicus with repeatedly denied intervention attempts and explicit limits imposed by the district court.
  4. Class-action exception is inapplicable.
    Devlin v. Scardelletti does not extend beyond the class-action setting (per U.S. ex rel. Eisenstein v. City of New York), and the Coalition is not “bound” by the decree in the sense that justified Devlin.
  5. The district court cannot confer appellate rights where jurisdiction is absent.
    Although the district court suggested the Coalition could appeal, the Sixth Circuit treats appellate jurisdiction as non-waivable and rule-bound. Prior Sixth Circuit language inviting the Coalition to “request intervention ‘for the limited purpose of appeal’” is read literally: it describes the correct mechanism (intervention), not an alternative to it.
  6. Institutional concern: resisting “litigating amicus curiae.”
    Quoting United States v. Michigan, 940 F.2d 143, the panel explicitly rejects the expansion of amici into quasi-parties through “judicial fiat,” emphasizing that Rule 24’s structure must control.

3.3 Impact

Although “NOT RECOMMENDED FOR PUBLICATION,” the opinion is practically significant in at least three ways:

  • Consent decree practice (especially in institutional or resource-management litigation): Groups permitted to lodge objections as amici cannot treat that participation as a procedural equivalent to intervention. If an organization wants appellate review of a decree’s entry, it must build a record through a proper Rule 24 motion (even if “for the limited purpose of appeal”).
  • Clarification of Sixth Circuit’s “de facto party” language: The decision constrains overreading of City of Cleveland v. Ohio by tying “de facto party” status to circumstances where the appellant was already a party and central to the controversy. This curbs attempts by non-parties to invoke “treated like a party” arguments based solely on being heard.
  • Environmental and recreational stakeholder strategy in treaty-rights and public-resource disputes: The Coalition’s inability to appeal means future stakeholder groups must decide early whether to remain amici (influencing the court without party burdens) or pursue intervention (accepting Rule 24’s requirements, including demonstrating a protectable interest and inadequate representation).

4. Complex Concepts Simplified

  • Amicus curiae (“friend of the court”): A non-party who may assist the court (briefing, information) but ordinarily does not control claims, cannot demand relief, and—crucially here—cannot appeal as of right.
  • Intervention (Fed. R. Civ. P. 24): The formal procedure by which a non-party becomes a party. Intervention as of right requires meeting a four-factor test; permissive intervention is discretionary and requires a common question of law/fact plus consideration of delay/prejudice.
  • Appellate jurisdiction: The appellate court’s legal power to hear a case. If jurisdiction is missing (e.g., because the appellant is a non-party who never intervened), the court must dismiss—even if the underlying issues are important.
  • “De facto party”: A narrow concept sometimes applied when a participant is effectively treated as a party in substance. This opinion underscores that extensive participation alone does not create party status when the participant is formally and repeatedly limited to amicus status.
  • Devlin / class-action objector exception: In certain mandatory class actions, nonnamed class members can appeal settlement approval because they are bound by the judgment. The Sixth Circuit stresses that this rationale does not extend to ordinary amici in non-class litigation.

5. Conclusion

The Sixth Circuit’s central takeaway is procedural but consequential: an amicus curiae—no matter how involved—cannot appeal the entry of a consent decree without first intervening under Rule 24. The court rejects efforts to obtain appellate review through (i) district-court permission, (ii) “de facto party” characterizations untethered from actual party status, or (iii) class-action analogies under Devlin v. Scardelletti.

By insisting on Rule 24’s formal gateway and reaffirming limits on “litigating amicus curiae,” the opinion reinforces orderly appellate practice in complex public-law cases—especially those resolved through negotiated decrees binding sovereigns and managing shared natural resources.