United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

 Filed December 5, 2022

No. 20-5291

HUMANE SOCIETY OF THE UNITED STATES, ET AL.,

APPELLANTS

v.

UNITED STATES DEPARTMENT OF AGRICULTURE, ET AL.,

APPELLEES

Appeal from the United States District Court

for the District of Columbia

(No. 1:19-cv-02458)

On Petition for Rehearing and Motion to Intervene

Before: MILLETT* and RAO**, Circuit Judges; and TATEL*,

Senior Circuit Judge

O R D E R

Upon consideration of the Tennessee Walking Horse

National Celebration Association’s (“Association”) motion to

intervene, the responses thereto, and the reply; the Association’s

lodged petition for rehearing and rehearing en banc; and

appellees’ petition for panel rehearing filed on October 6, 2022,

it is
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ORDERED that the motion to intervene be denied. It is

FURTHER ORDERED that appellees’ petition for panel

rehearing be denied. On remand, the district court may consider

all remedial issues, including the question of whether remand to

the agency without vacatur is appropriate under the criteria

established by Circuit precedent.

Per Curiam

FOR THE COURT:

Mark J. Langer, Clerk 

BY: /s/

Michael C. McGrail

Deputy Clerk

* A statement by Senior Circuit Judge Tatel, with whom Circuit

Judge Millett joins, concurring in the denial of the motion to

intervene, is attached.

** Circuit Judge Rao would grant the motion to intervene and

has abstained from voting on the petition for panel rehearing. A

statement by Circuit Judge Rao, dissenting from the denial of

the motion to intervene, is attached.
TATEL, Senior Circuit Judge, with whom Circuit Judge

MILLETT joins, concurring in the denial of the motion to 

intervene: Our dissenting colleague believes that this case 

“implicates important questions about the timing and finality 

of administrative rulemaking.” Dissenting Op. at 1. But the 

Department of Agriculture (“the Department”), whose 2017 

rule is at issue, disagrees. After consulting with the Solicitor 

General, it has foregone en banc review and instead decided

that the best way to defend its withdrawal of the rule was to file 

a petition for rehearing asking the panel to clarify that, on 

remand, “the district court should be allowed to consider all 

remedial issues, including the question of whether remand to 

the agency without vacatur is appropriate.” Pet. for Reh’g at 1. 

Not only have we granted that request, but proposed intervenor, 

the Tennessee Walking Horse National Celebration 

Association (“the Association”), advises that it would be 

satisfied with just that relief. See Association Pet. for Reh’g at 

15–16 (requesting that “at a minimum” the district court 

“should have maximum flexibility on remand to address 

competing considerations and determine the best use of the 

parties’ and the court’s resources in fashioning a remedy”). 

This modest request makes sense given that the Department is 

in the late stages of developing a rule addressing the same topic 

as the 2017 rule, a fact the district court can consider when 

determining the proper remedy. Under these circumstances, I 

cannot imagine why we would allow the Association to 

intervene so that it can file an en banc petition that could not 

possibly satisfy our rigorous standards. See Fed. R. App. P. 

35(a) (granting en banc rehearing only “when necessary to 

secure . . . uniformity of the court’s decisions” or to decide 

“question[s] of exceptional importance”). 

Our case law, moreover, supports denying intervention

here. Because no rule governs appellate intervention, we 

consider the “policies underlying intervention” in the district 

courts when evaluating a motion to intervene. Automobile 

Workers v. Scofield, 382 U.S. 205, 217 n.10 (1965). Those 
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policies include consideration of the legal interest the parties 

seek to protect and whether the motion is “timely.” Fed R. Civ. 

P. 24(a)(2). The timeliness requirement is dispositive here.

Under our court’s standard practice, we grant motions to 

intervene at the appellate stage only in “exceptional case[s] for 

imperative reasons.” Amalgamated Transit Union 

International, AFL-CIO v. Donovan, 771 F.2d 1551, 1552 

(D.C. Cir. 1985) (per curiam) (internal quotation marks 

omitted). Moreover, a “motion for leave to intervene [that] 

comes after the court of appeals has decided a case,” like here, 

“should be even more disfavored.” Id. at 1553.

The case our dissenting colleague relies on, Cameron v. 

EMW Women’s Surgical Center, 142 S. Ct. 1002 (2022), does 

not require us to grant the motion to intervene. In Cameron, 

where the Supreme Court allowed the Kentucky attorney 

general to intervene post-merits after the Kentucky secretary 

for Health and Human Services declined to continue defending 

the constitutionality of a state law, the proposed intervenor’s 

legal interest was paramount. The Court repeatedly placed its 

focus on the “substantial legal interest that sounds in deeper, 

constitutional considerations,” and emphasized the “strength” 

of the Kentucky attorney general’s interest. Cameron, 142 S. 

Ct. at 1010–12. As the Court explained, a “State’s opportunity 

to defend its laws in federal court should not be lightly cut off.” 

Id. at 1011. No such sovereignty concerns are present in this 

case. 

Even were we to focus, as does the dissent, on Cameron’s 

timeliness inquiry in isolation—that is, unconnected to its 

earlier discussion of sovereignty—it still does not require us to 

permit intervention. Dissenting Op. at 3. Explaining that 

“timeliness is to be determined from all the circumstances,” the

Court in Cameron concluded that the attorney general’s motion 

was timely because he sought to intervene “‘as soon as it 
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became clear’” that Kentucky’s interests “‘would no longer be 

protected’” by the parties remaining in the case—that is, when 

the Health and Human Services secretary declined to continue 

pursuing review. Cameron, 142 S. Ct. at 1012 (quoting United 

Airlines, Inc. v. McDonald, 432 U.S. 385, 394 (1977)). Here, 

by contrast, the Department continued pursuing review: it 

petitioned for rehearing. 

According to the dissent, this was the wrong kind of 

review. Because the Department’s petition focuses on remedy 

as opposed to the merits, the Association must be permitted to 

intervene to defend its own interests. Dissenting Op. at 3, 4–5. 

But this would allow intervention in situations even broader 

than in Cameron. It would allow a third party to intervene not 

because an agency failed to move for additional review, but 

because the agency failed to move for review in the third 

party’s preferred way. The problem with this reasoning is, 

again, timeliness. The Association has long been on notice that 

its interests were not the same as the Department’s, a 

government agency bound to represent the “interests of the 

American people.” Fund for Animals, Inc. v. Norton, 322 F.3d 

728, 736 (D.C. Cir. 2003). In representing the public, the 

Department may favor different arguments than a private third

party. Dimond v. D.C., 792 F.2d 179, 193 (D.C. Cir. 1986). For 

example, the Department may, as it apparently has, determine 

that the best way to defend its rule withdrawal is to convince 

the lower court to allow it to complete rulemaking for the 

replacement rule instead of vacating. It is not for the 

Association to now second guess the Department’s strategy by 

intervening. Aware from the beginning of this case that its 

interests may differ, the Association could have intervened in 

order to influence the way the Department defended the 2017 

rule withdrawal. An eleventh-hour motion to do so now is 

untimely. 
RAO, Circuit Judge, dissenting from the denial of the 

motion to intervene: I would grant the motion to intervene of 

the Tennessee Walking Horse National Celebration 

Association (“Association”). The Association’s interests were 

adequately represented by the government until this point, but 

now the Government has declined to seek rehearing en banc. 

The Association satisfies the requirements for intervention of 

right under Federal Rule of Civil Procedure 24(a)(2), and the 

Supreme Court’s recent decision in Cameron v. EMW 

Women’s Surgical Center, P.S.C., 142 S. Ct. 1002 (2022), 

makes clear the motion is timely. 

* * *

The Association is a nonprofit organization that runs the 

National Celebration, a show featuring Tennessee walking 

horses. The Association requests intervention to seek further 

review of this panel’s decision in Humane Society of the United 

States v. USDA, 41 F.4th 564 (2022), which holds the 

withdrawal of a rule promulgated under the Horse Protection 

Act was invalid. Beyond the specific rule at issue, the divided 

decision implicates important questions about the timing and 

finality of administrative rulemaking. The majority held that a 

rule is final after it is made available for public inspection in 

the Office of the Federal Register, even if it has not been 

published, and therefore at that stage can be withdrawn only by 

following notice and comment procedures. See id. at 575. The 

dissent maintained, however, that the decision contravened 

Kennecott Utah Copper Corp. v. Department of the Interior, 88 

F.3d 1191 (D.C. Cir. 1996) (per curiam), and was directly at 

odds with the Administrative Procedure Act, the Federal 

Register Act, and numerous decisions holding that a rule is 

final upon publication in the Federal Register. Humane Society, 

41 F.4th at 576–84 (Rao, J., dissenting); see also id. at 585 

(noting the majority’s decision “interferes with the current 

president’s authority to control the regulatory agenda of his 
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administration” and “has disturbing implications for due 

process in agency enforcement”).

The Association seeks intervention under Federal Rule of 

Civil Procedure 24(a)(2), which provides for intervention of 

right to anyone who, “[o]n timely motion,” (i) “claims an 

interest relating to the property or transaction that is the subject 

of the action,” and (ii) “is so situated that disposing of the 

action may as a practical matter impair or impede the movant’s 

ability to protect its interest,” unless (iii) “existing parties 

adequately represent that interest.” FED. R. CIV. P. 24(a).

Neither the plaintiffs nor the Government contest the 

Association meets the first two requirements because the rule

at issue would effectively ban from competition a substantial 

percentage of Tennessee walking horses, making it impossible 

for the Association to stage its show. Now that the Government 

has declined to seek further merits review of the panel decision, 

it is equally clear that the Government no longer adequately 

represents the Association’s interests. The only question is 

whether the Association acted “[o]n timely motion.” Id.

“Timeliness is an important consideration in deciding 

whether intervention should be allowed.” Cameron, 142 S. Ct. 

at 1012. But “timeliness is to be determined from all the 

circumstances and the point to which a suit has progressed is 

not solely dispositive.” Id. (cleaned up). Applying the 

standards in Cameron, the Association’s motion to intervene 

was timely.

We issued our panel opinion on July 22, 2022, and the 

Association moved to intervene of right shortly thereafter, on 

August 5. At the time, the Government had not indicated 

whether it would seek rehearing en banc. While the 

Government opposed intervention of right, it indicated it would 

not object to permissive intervention, particularly if we
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deferred consideration of the motion until after the deadline for 

seeking further review passed, on October 6, 2022. On that 

date, the Government filed a motion for panel rehearing, but 

only to amend our opinion “in a limited respect related to the 

issue of remedy.” The Government did not seek rehearing en 

banc or review of the panel decision on the merits. On that same 

day, with its motion for intervention pending, the Association 

lodged its petition for rehearing en banc. 

After Cameron, it is clear the Association is entitled to 

intervene. In that case, the Court permitted intervention by the 

Kentucky Attorney General following a Sixth Circuit decision, 

because that was the point at which it became clear that the

state officials defending the law would not seek rehearing en 

banc or a writ of certiorari. Cameron, 142 S. Ct. at 1008. The 

Court emphasized that “[t]he attorney general’s need to seek 

intervention did not arise until the secretary ceased defending 

the state law, and the timeliness of his motion should be 

assessed in relation to that point in time.” Id. at 1012. In light 

of the circumstances, the attorney general’s motion to intervene 

was timely. See id. at 1013. The facts here are very similar. The 

Association moved quickly when it realized the Government 

might not seek rehearing en banc, filing its motion to intervene 

within two weeks of our panel opinion and long before the 

deadline for further review expired. The Association’s motion 

was timely because the “need to seek intervention did not arise 

until the [Government] ceased defending the [rule].”1 Id. at 

1012.

1 Despite the obvious applicability of Cameron, the concurring 

opinion maintains that under circuit law, an entirely different 

standard applies, and that we may grant a motion to intervene at the 

appellate stage only in “exceptional cases for imperative reasons.” 

Concurring Op. 2 (quoting Amalgamated Transit Union Int’l, AFLCIO v. Donovan, 771 F.2d 1551, 1552 (D.C. Cir. 1985) (per curiam))
4

The concurring opinion offers two theories to distinguish 

Cameron. First, the concurrence argues Cameron rested on 

“sovereignty concerns” associated with the Kentucky Attorney 

General’s interest in defending the constitutionality of state 

laws. See Concurring Op. 2. That is incorrect. The timeliness 

analysis in Cameron was analytically separate from the part of 

the opinion discussing Kentucky’s sovereign interest. Justice 

Kagan emphasized this point, noting that “[t]he considerations 

governing intervention motions—applying equivalently to any 

person seeking to intervene, including the attorney general—

show why the Sixth Circuit went wrong in closing off the suit.” 

Id. at 1019 (Kagan, J., concurring in the judgment). Moreover,

the Court expressly analogized to a case involving intervention 

by a private party. See id. at 1012 (majority opinion) (citing 

United Airlines, Inc. v. McDonald, 432 U.S. 385, 396 (1977)).

Nothing in the Court’s opinion limits its timeliness analysis to

cases involving public officials or state sovereign interests.

Second, and more puzzling still, the concurring opinion 

relies on the Government’s decision to petition for panel 

rehearing to amend the majority opinion “in a limited respect,”

(cleaned up). This approach mirrors that taken by the Sixth Circuit 

in the opinion reversed by the Supreme Court in Cameron. Indeed, 

that panel also repeatedly cited to Donovan for the proposition that 

motions to intervene filed after appellate judgment are disfavored. 

See EMW Women’s Surgical Ctr., P.S.C. v. Friedlander, 831 F. 

App’x 748, 750 (6th Cir. 2020). Yet the Supreme Court flatly 

concluded that the Sixth Circuit’s “assessment of timeliness was 

mistaken.” Cameron, 142 S. Ct. at 1012–13. To the extent that 

Donovan is inconsistent with Cameron, it is no longer good law. And 

in any event, Donovan is distinguishable from this case because the 

Government there, after losing on appeal, sought further merits 

review by filing a motion for panel rehearing and for rehearing en 

banc, so there was no basis on which to grant the motion to intervene. 

See 771 F.2d at 1552 & n.2.
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suggesting this request somehow resolved the Association’s

grounds for intervention. See Concurring Op. 1, 3. This is 

plainly not true. The Association was first and foremost 

concerned with securing further merits review of the panel 

decision, review it was entitled to seek as an intervenor under 

Cameron. The Association’s entire petition for rehearing 

argues for en banc review to resolve the panel majority’s 

inconsistency “with prior decisions of both this Court and other 

circuits” and the “needless uncertainty” the opinion generates 

“about the point at which agency actions become final.” Only 

at the end of its petition did the Association briefly argue that 

we should at a minimum grant the same relief sought by the 

Government. But the Association nowhere suggested that it 

would be “satisfied with just that relief.” Concurring Op. 1. 

Ultimately, the concurring opinion’s argument reduces to 

the proposition that intervention is inappropriate if an existing 

party has sought any review of the panel decision, no matter 

how limited. That rule would render Cameron a dead letter, 

allowing existing parties to forestall intervention simply by 

requesting the panel amend a sentence or two in its opinion.

Finally, I note that denying intervention in this context

may result in greater litigation burdens. Prospective intervenors 

may find it necessary to seek intervention at the outset of an 

appeal, or perhaps even earlier, to guard against the possibility 

that the party representing their interests will abandon further 

review. But at the earlier stage of litigation some parties may 

be denied intervention because the “existing parties adequately 

represent [their] interest[s].” FED. R. CIV. P. 24(a)(2). The

possibility of this catch-22 will inevitably multiply requests for

early and otherwise unnecessary intervention. 

* * *
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Following the Supreme Court’s simple directive in 

Cameron, I would grant the Association’s motion to intervene 

so that it may petition for rehearing en banc on this important 

issue of administrative law.