People for the Ethical Treatment of Animals v. Lawrence A. Tabak

United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued April 25, 2024 Decided July 30, 2024
No. 23-5110
PEOPLE FOR THE ETHICAL TREATMENT OF ANIMALS, ET AL.,
APPELLANTS
v.
LAWRENCE A. TABAK, IN HIS OFFICIAL CAPACITY AS ACTING
DIRECTOR OF THE NATIONAL INSTITUTES OF HEALTH AND
XAVIER BECERRA, IN HIS OFFICIAL CAPACITY AS SECRETARY
OF THE U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES,
APPELLEES
Appeal from the United States District Court
for the District of Columbia
(No. 1:21-cv-02380)
Stephanie Krent argued the cause for appellants. With her
on the briefs were Ashley Ridgway, Katherine A. Fallow,
Alexia Ramirez, and Jameel Jaffer.
Sophia Cope and David Greene were on the brief for amici
curiae Electronic Frontier Foundation and Foundation for
Individual Rights and Expression in support of appellants.
Jennifer L. Utrecht, Attorney, U.S. Department of Justice,
argued the cause for appellees. With her on the brief were

-- 1 of 18 --

2
Brian M. Boynton, Principal Deputy Assistant Attorney
General, and Daniel Tenny, Attorney.
Before: HENDERSON, MILLETT, and GARCIA, Circuit
Judges.
Opinion for the Court filed by Circuit Judge GARCIA.
GARCIA, Circuit Judge: Appellants are the nonprofit
People for the Ethical Treatment of Animals (“PETA”) and two
animal rights advocates, Madeline Krasno and Ryan Hartkopf,
who use social media to advocate against animal testing. They
frequently commented on the official Facebook and Instagram
pages of appellee National Institutes of Health (“NIH”),
criticizing NIH’s funding of research conducted on animals.
Those efforts ran headfirst into NIH’s social media moderation
policy, which prohibits, as relevant here, “off-topic posts.” To
enforce this policy, NIH deployed keyword filters—which
automatically hide all comments with the chosen keywords—
to filter out comments containing words that frequently
appeared in posts that it considered “off-topic,” such as the
terms “animal,” “testing,” and “cruel.” Appellants’ and all
other users’ comments containing those words were thus
filtered out and not viewable to the public.
Appellants argue that NIH’s policy violates the First
Amendment. We must decide what type of forum NIH’s
comment threads are and whether NIH’s social media
moderation policy, as implemented through its keyword filters,
is constitutional. The district court held that the comment
threads were limited public forums and upheld NIH’s speech
restrictions as reasonable.
We agree that NIH’s comment threads are limited public
forums because the government has signaled its intent to limit
the discussion on those threads to specific subjects. But we

-- 2 of 18 --

3
hold that NIH’s “off-topic” restriction, as implemented through
its keyword filters, is not reasonable in light of the purpose of
the forum and is therefore unconstitutional under the First
Amendment.
I
A
The parties stipulated to the following facts. See Joint
Stipulation of Facts (“Jt. Stip.”), People for the Ethical
Treatment of Animals v. Tabak (“PETA”), No. 21-cv-2380
(D.D.C. Feb. 11, 2022), ECF No. 28. NIH is the primary
federal agency charged with performing and supporting
biomedical and behavioral research. It maintains verified
Facebook and Instagram pages to “communicate and interact
with citizens” about agency-related work. Jt. Stip. ¶ 36. NIH
often posts highlights of NIH-funded researchers and their
research, interviews with experts, and news updates. Posts are
viewable by the public, and Facebook and Instagram users can
comment on them.
NIH’s Comment Guidelines govern comments on NIH’s
social media. See NIH Comment Guidelines, (last updated
March 13, 2019), https://perma.cc/YN6J-8GFH. Those
publicly available guidelines “encourage” the public to “share
[their] thoughts and ideas” and state that “NIH blogs are not
intended to serve as public forums.” Id. To “encourage
respectful and constructive dialogue,” the Guidelines prohibit
“vulgar, obscene, profane, threatening, or abusive language,”
“discriminatory language,” “endorsements of commercial
products,” “repetitive posts,” “spam or undecipherable
language,” “links to external sites,” and, most relevant here,
“off-topic posts.” Id. (capitalization modified). The
Guidelines also ask that “comments be respectful and relevant
to the specific topic.” Id.

-- 3 of 18 --

4
Facebook and Instagram accountholders—such as NIH
here—have at their disposal several tools to moderate
comments. Accountholders can block individual users and
manually delete or hide comments. They can also turn on the
platforms’ default filters, which hide from public view
comments that contain profanity or other offensive words. On
Facebook, the hidden comment is then viewable only by the
user and their friends. On Instagram, users may view hidden
comments by scrolling to the bottom of a comment thread and
clicking “view hidden comments.” NIH enabled the platform’s
default filters here.
Accountholders may also use custom keyword filters—the
primary focus of this case. An accountholder can specify a
custom list of keywords to be filtered out; any past or future
comment containing those keywords is then automatically
hidden. On Facebook, a comment hidden by custom keyword
filters is automatically hidden from public view but remains
visible to the user who posted the comment and their friends.
On Instagram, a comment hidden by custom keyword filters is
visible only to the user and the account holder if they choose to
“view hidden comments.” Typically, the user who posted the
filtered-out comment is not notified. NIH created custom
keyword filters to implement its Commenting Guidelines.
As of the date of the complaint, September 9, 2021, NIH’s
Facebook keyword filters consisted of the following words:
“PETA, PETALatino, animal(s), animales, animalitos, cats,
gatos, chimpanzee(s), chimp(s), hamster(s), marmoset(s),
monkey(s), monkies, mouse, mice, primate(s), sex
experiments, cruel, cruelty, revolting, torment(ing), torture(s),
torturing, #believemothers, marijuana, cannabis, Hitler, nazi,”
as well as the names of two researchers who have conducted
experiments on monkeys (“Suomi,” “Harlow”), various URL
parts (e.g., www., gmail, .org, .com), and expletives. Jt. Stip.
¶ 58 (capitalization modified); see Compl., Attachment 1. On

-- 4 of 18 --

5
Instagram, the following words were filtered: “PETA,
#stopanimaltesting, #stoptesting, #stoptestingonanimals,
animal(s), chimpanzee(s), chimps, monkey(s), experiment,
hurt(ing), kill, stop, test(ing), testing facility, tortur(ing), pedos,
rapist,” as well as four emojis and an expletive. Jt. Stip. ¶ 58
(capitalization modified); see Compl., Attachment 2. NIH said
it added these terms “to target comments frequently made on
NIH’s social media pages that the NIH believes would violate
its comment moderation guidelines.” Jt. Stip. ¶ 58. While NIH
maintains it has the “authority to manually review any and all
comments before and after they are posted,” “in practice” NIH
implemented its guidelines only through use of keyword filters.
Id. ¶ 61.
B
On September 9, 2021, PETA, Krasno, and Hartkopf sued
NIH in district court, alleging that NIH’s use of keyword filters
violated their First Amendment rights. PETA is a nonprofit
organization dedicated to advocating for animal rights, and the
individual appellants are animal rights advocates. Appellants
use social media to raise awareness for their causes, which
include opposing animal testing and animal mistreatment in
laboratories. In particular, appellants frequently comment on
NIH’s social media pages to protest NIH’s funding of animal
testing. Many of their comments have been automatically
filtered out by NIH’s keyword filters. For example, Krasno
attempted to comment the following on an NIH Instagram post
depicting a cell infected with COVID-19: “It’s time we had an
open conversation about all the animal testing you fund. What
a waste of life and resources.” Jt. Stip. ¶ 73. That comment
was automatically hidden from public view because “animal”
and “testing” were on NIH’s keyword filters list. Id.
In December 2021, NIH removed “PETA” and
“PETALatino” from its keyword filters on both platforms and

-- 5 of 18 --

6
removed “#stopanimaltesting” and “#stoptesting” from its
Instagram filters. Jt. Stip. ¶ 60. The parties cross-moved for
summary judgment. The district court granted summary
judgment to the government, holding that NIH’s keyword
filters were viewpoint-neutral and reasonable restrictions in a
limited public forum. See PETA, 2023 WL 2809867, at *14
(D.D.C. Mar. 31, 2023). This appeal followed.1
II
We review the district court’s grant of summary judgment
in favor of the government de novo, Bauer v. Fed. Deposit Ins.,
38 F.4th 1114, 1121 (D.C. Cir. 2022), and have an “obligation
to ‘make an independent examination of the whole record,’”
Liberty Lobby, Inc. v. Rees, 852 F.2d 595, 598 (D.C. Cir. 1988)
(quoting Bose Corp. v. Consumers Union of United States, Inc.,
466 U.S. 485, 499 (1984)).
A
The speech restrictions challenged here apply only to
NIH’s comment threads, which the parties agree are
government-controlled property. See Appellants’ Brief 33;
Appellee’s Brief 26. On government-controlled property, the
standard by which speech restrictions are evaluated “depends
on the nature of the relevant forum.” Cornelius v. NAACP
Legal Def. & Educ. Fund, Inc., 473 U.S. 788, 800 (1985).
1 Appellants’ complaint also named the Department of Health
and Human Services (“HHS”) as a defendant, but the district court’s
order did not resolve the claims against HHS. This raised the
question whether the district court’s order is final and ready for our
review under 28 U.S.C. § 1291. To resolve this issue, appellants,
with the government’s consent, filed a motion to dismiss their claims
against HHS in district court, which the district court granted.
Minute Order, PETA, No. 21-cv-2380 (D.D.C. Jan. 11, 2024).

-- 6 of 18 --

7
Traditional public forums—like parks and sidewalks—are
“places which by long tradition . . . have been devoted to
assembly and debate.” Perry Educ. Ass’n v. Perry Loc.
Educators’ Ass’n, 460 U.S. 37, 45 (1983). In such forums, the
government may “impose reasonable time, place, and manner
restrictions on private speech, but restrictions based on content
must satisfy strict scrutiny, and those based on viewpoint are
prohibited.” Minn. Voters All. v. Mansky, 585 U.S. 1, 11
(2018). That same strict standard applies to a designated public
forum, which is a space that has “‘not traditionally been
regarded as a public forum’ but which the government has
‘intentionally opened up for that purpose.’” Id. (quoting
Pleasant Grove City v. Summum, 555 U.S. 460, 469 (2009)).
In contrast, a nonpublic forum, such as a museum or office,
is a place “not by tradition or designation” a public forum and
one in which the government may restrict speech so long as the
“regulation on speech is reasonable and not an effort to
suppress expression merely because public officials oppose the
speaker’s view.” Perry, 460 U.S. at 46. Finally, what we have
sometimes termed a “hybrid case” is a “limited public forum,
in which the Government has ‘create[d] a forum that is limited
to use by certain groups or dedicated solely to the discussion of
certain subjects.’” Price v. Garland, 45 F.4th 1059, 1068 (D.C.
Cir. 2022) (quoting Pleasant Grove, 555 U.S. at 470)
(alteration in original). As in nonpublic forums, speech
restrictions in limited forums need only be viewpoint neutral
and “reasonable in light of the purpose served by the forum.”
Good News Club v. Milford Cent. Sch., 533 U.S. 98, 106–07
(2001) (quoting Cornelius, 473 U.S. at 806).
Appellants argue that NIH’s comment threads are
designated public forums; the government contends they are
limited forums. The district court agreed with the government
on this threshold question, and so do we.

-- 7 of 18 --

8
“The touchstone for determining whether government
property is a designated public forum [or instead a nonpublic
or limited forum] is the government’s intent in establishing and
maintaining the property.” Stewart v. D.C. Armory Bd., 863
F.2d 1013, 1016 (D.C. Cir. 1988). The government does not
create a designated public forum “by inaction or by permitting
limited discourse” but rather “only by intentionally opening a
nontraditional forum for public discourse.” Cornelius, 473
U.S. at 802. Put otherwise, “the government must make an
affirmative choice to open up its property for use as a public
forum.” United States v. Am. Libr. Ass’n, 539 U.S. 194, 206
(2003) (plurality opinion) (emphasis added). To discern the
government’s intent, we look at the government’s “stated
purpose” and other “‘objective indicia of intent’ such as ‘the
nature of the property, its compatibility with expressive
activity, and the consistent policy and practice of the
government.’” Bryant v. Gates, 532 F.3d 888, 896 (D.C. Cir.
2008) (quoting Stewart, 863 F.2d at 1016–17) (emphasis
omitted).
Here, those factors demonstrate that NIH sought to limit
the forum “solely to the discussion of certain subjects” and that
it is therefore a limited public forum. Pleasant Grove, 555 U.S.
at 470.
To begin, the government stated in its Comment
Guidelines that its “blogs are not intended to serve as public
forums.” NIH Comment Guidelines, supra. It further stated
that the purpose of its social media pages is to “disseminate
health information by communicating important public health
information” and “engaging the public for educational
purposes about public health,” Jt. Stip. ¶ 87, which suggests
NIH was limiting the pages “solely to the discussion of certain
subjects,” Pleasant Grove, 555 U.S. at 470, namely those
relevant to NIH’s public health work.

-- 8 of 18 --

9
NIH also “prospectively and categorically set subject
matter regulations” to effectuate those stated aims.
Archdiocese of Wash. v. Wash. Metro. Area Transit Auth., 897
F.3d 314, 324 (D.C. Cir. 2018). NIH published online its
Comment Guidelines, which prohibit several categories of
speech including off-topic posts; endorsements of commercial
products; and profane, repetitive, or discriminatory comments.
See NIH Comment Guidelines, supra; see also id. (“We ask
that your comments be respectful and relevant to the specific
topic.”). Moreover, as detailed further below, NIH sought to
enforce those guidelines by using a range of keyword filters.
The guidelines and use of keyword filters indicate that the
comment sections are limited to discussion of certain subjects
rather than open “for use by the public as a place for expressive
activity” in general. Perry, 460 U.S. at 45.
Several courts have held that when the government
indicates its intent to limit discussion to certain subject matter
by setting restrictions in analogous situations, the forum is a
limited public forum. One common example is when a school
board limits public comment during its meetings to only those
topics on its agenda. See Barrett v. Walker Cnty. Sch. Dist.,
872 F.3d 1209, 1225 (11th Cir. 2017) (school board meeting
was limited forum in part because the board “limits discussion
to certain topics”); see also Steinburg v. Chesterfield Cnty.
Plan. Comm’n, 527 F.3d 377, 385 (4th Cir. 2008) (similar);
Galena v. Leone, 638 F.3d 186, 199 (3d Cir. 2011) (similar).
In the social media context, courts have also found that the
comment threads of government social media pages are
designated public forums when the pages are open for
comment without restrictions and limited public forums when
the government prospectively sets restrictions. See, e.g.,
Garnier v. O’Connor-Ratcliff, 41 F.4th 1158, 1178–79 (9th
Cir. 2022) (pages were designated public forums when
“available to the public without any restriction on the form or

-- 9 of 18 --

10
content of comments” but became limited forums when the
government used word filters and other speech restrictions),
vacated and remanded on other grounds, 601 U.S. 205 (2024);
Davison v. Randall, 912 F.3d 666, 682 (4th Cir. 2019)
(comment section held to be designated public forum when the
government “placed no restrictions” on use and access to the
page), as amended (Jan. 9, 2019); see also Knight First Amend.
Inst. at Columbia Univ. v. Trump, 928 F.3d 226, 237 (2d Cir.
2019) (similar), judgment vacated on other grounds, 141 S. Ct.
1220 (2021).
Despite those stated policies, and to distinguish the cases
just discussed, appellants argue that NIH’s enforcement of
those restrictions was inconsistent to an extent that shows
NIH’s true intent was to make the comment threads designated
public forums and block only animal advocacy speech.
Appellants’ Brief 35–39. As support, appellants point to cases
holding that the government created designated public forums
when it announced speech restrictions but then ignored those
restrictions in practice. See, e.g., Grace Bible Fellowship, Inc.
v. Me. Sch. Admin. Dist. No. 5, 941 F.2d 45, 47 (1st Cir. 1991));
Hopper v. City of Pasco, 241 F.3d 1067, 1081 (9th Cir. 2001);
see also Lebron v. Wash. Metro. Area Transit Auth., 749 F.2d
893, 896 (D.C. Cir. 1984). And as proof of inconsistent
enforcement, appellants emphasize that a substantial number of
comments that seemingly violate NIH’s guidelines remained
on NIH’s posts. See, e.g., Jt. Stip. Ex. 56 at 4.
We disagree. This is not a case in which the government
made either no effort, or a minimal one, to enforce its stated
policy. Rather, NIH attempted to implement its stated policies
through keyword filters, which apply across the whole page
and filter all comments containing those words. See Jt. Stip.
¶ 30. Those filters captured several content areas other than the
challenged animal-testing-related filters, such as profanity,
drug-related words, #believemothers, several emojis, offensive

-- 10 of 18 --

11
words, and terms related to external links. See Compl.,
Attachment 1 (Facebook filters); Compl., Attachment 2
(Instagram filters). NIH also enforced its rules by enabling the
default Facebook and Instagram filters that restrict offensive
language. Jt. Stip. ¶¶ 56–57.
It is true that a number of comments that seemingly violate
NIH’s stated policy remained on NIH posts, but that fact has
less salience here than did similar facts in the cases on which
appellants rely. For example, in Hopper, the Ninth Circuit
found that a city-owned art exhibit, despite having a stated
policy against controversial works, was a designated public
forum because the city had never enforced that policy until it
excluded the plaintiffs’ works. 241 F.3d at 1071, 1078.
Importantly, the city signed a contract with each individual
artist to display their work but had never before applied its
stated policy. Id. at 1072. Those facts supported the inference
that the government did not truly intend to enforce that policy
and instead created a public forum. Id. at 1078, 1080; see also
Grace Bible Fellowship, 941 F.2d at 46 (plaintiffs sought and
were denied a lease to use school facilities for religious
purposes when other speakers using facilities for expressive
purposes were approved); Lebron, 749 F.2d at 895 & n.6
(plaintiff sought and was denied approval for a political bus
advertisement when prior political advertisements were
approved).
Here, by contrast, NIH did not affirmatively decide not to
enforce its guidelines, nor did it approve the specific comments
that violated its guidelines. Rather, the record shows that
because NIH lacked “the resources to manually” review each
of the innumerable posted comments, it attempted to
prospectively block—through keyword filters—a variety of
comments that it believed would violate its guidelines. See
Compl., Attachment 1 (Facebook filters); Compl., Attachment
2 (Instagram filters). That enforcement was certainly

-- 11 of 18 --

12
imperfect, and some speech that contravenes NIH’s policies
was not blocked or removed. But that fact is far less relevant
here because, given the context, it does not reflect an
“affirmative choice” by NIH to allow the violative comments.
Am. Libr. Ass’n, 539 U.S. at 206. As the district court aptly put
it, a court’s “examination of the government’s actual practice
in enforcing its policy is not a gotcha game; rather it is a tool
to smoke out the government’s ‘intent’ with regard to the
forum’s purpose—the ‘touchstone’ of the forum inquiry.”
PETA, 2023 WL 2809867, at *9 (quoting Bryant, 532 F.3d at
895–96).
In short, because NIH attempted to remove a range of
speech violating its policies, and because the existence of
violative speech in the forum bears less on the government’s
intent here than it did in the appellants’ cited cases, we find
sufficient evidence that the government intended to limit the
forum to only speech that meets its public guidelines.
This analysis echoes the Supreme Court’s plurality
opinion in American Library Association. See 539 U.S. at 208.
There, petitioners argued that public library computers were
designated public forums because after the libraries made
internet access available to patrons, they had restricted access
to only one “inappropriate” subject (pornography) but had not
made a judgment about whether the vast amount of remaining
content available on the internet was appropriate. Id. at 206–
07. The Supreme Court held that this underinclusivity did not
make the computers designated public forums. Id. at 208; see
id. at 206. So too here. While NIH’s filters certainly do not
capture all types of off-topic or other comments that might
violate NIH’s Guidelines, they nonetheless still support finding
that the government intended to keep its comment sections a
limited public forum.

-- 12 of 18 --

13
Finally, whether the forum is “compatible with expressive
activity” factors into the forum analysis. Stewart, 863 F.2d at
1019. We recognize social media is inherently compatible with
expressive activity given it is one of the “most important
places . . . for the exchange of views.” Packingham v. North
Carolina, 582 U.S. 98, 104 (2017). This factor, however, is
not dispositive on its own. See Stewart, 863 F.2d at 1019
(noting that “compatibility provides some evidence of the
government’s intent”). After considering NIH’s stated
purpose, policy, and enforcement efforts, we conclude that
NIH intended to create a forum limited “solely to the discussion
of certain subjects.” Pleasant Grove, 555 U.S. at 470.
B
In a limited public forum, speech restrictions may be
“based on subject matter” if the restrictions are “reasonable in
light of the purpose served by the forum” and “viewpoint
neutral.” Cornelius, 473 U.S. at 806. Appellants do not
challenge the entirety of NIH’s Comment Guidelines; they
focused solely on the constitutionality of the off-topic
restriction as implemented by the keyword filters. We
therefore examine only that restriction.
Reasonableness is to be assessed in light of the purpose of
the forum, which here is to “communicate and interact with
citizens,” Jt. Stip. ¶ 36, and to “encourage respectful and
constructive dialogue” through the public’s comments, NIH
Comment Guidelines, supra. Reasonableness in this context is
thus necessarily a more demanding test than in forums that
have a primary purpose that is less compatible with expressive
activity, like the football stadium “forum” in Stewart. See 863
F.2d at 1019–20 (noting that a forum’s compatibility with
expressive activity factors into both forum and reasonableness
analysis). In service of those purposes, NIH’s off-topic
restriction furthers the “permissible objective[s],” Mansky, 585

-- 13 of 18 --

14
U.S. at 13, of creating comment threads dedicated to each
post’s topic and allowing the public to engage on that topic,
instead of being distracted or overwhelmed by off-topic
comments.
But NIH must “draw a reasonable line,” id. at 16, informed
by “objective, workable standards,” id. at 21, between what is
considered on-topic and what is considered off-topic.
“Although there is no requirement of narrow tailoring,” the
government “must be able to articulate some sensible basis for
distinguishing what may come in from what must stay out.” Id.
at 16. This NIH has not done.
In the context of NIH’s posts—which often feature
research conducted using animal experiments or researchers
who have conducted such experiments—to consider words
related to animal testing categorically “off-topic” does not
“ring[] of common-sense.” United States v. Kokinda, 497 U.S.
720, 734 (1990) (plurality opinion) (internal quotation marks
omitted). For example, consider NIH’s July 20, 2021
Instagram post, which featured a photo of the eye of a
zebrafish. Jt. Stip., Ex. 9. The caption read, in part: “This
picture of an anesthetized adult zebrafish was taken with a
powerful microscope that uses lasers to illuminate the fish.” Id.
It is unreasonable to think that comments related to animal
testing are off-topic for such a post. Yet a comment like
“animal testing on zebrafish is cruel” would have been filtered
out because “animal,” “testing,” and “cruel” are all blocked by
NIH’s keyword filters.
The government admits that animal testing comments
would be on-topic for that post and instead argues that the off-
topic rule is still reasonable because a reasonable policy may
be both over- and underinclusive. See Oral Argument Tr. 31:1–
12. That argument assumes the zebrafish post is an outlier. But
the record indicates otherwise. A substantial portion of the

-- 14 of 18 --

15
NIH posts included in the stipulated record either directly
depict animals or discuss research conducted on animals. See
Jt. Stip. Exs. 8–9 (posts depicting animals); id., Exs. 6, 11, 32,
41, 52, 56–57 (posts discussing research conducted on
animals); see also Appellants’ Brief 26–27 n.10. To say that
comments related to animal testing are categorically off-topic
when a significant portion of NIH’s posts are about research
conducted on animals defies common sense.
Worse, the government fails to provide any definition of
“off-topic” in its Comment Guidelines, to its social media
moderators, or even in this litigation. See Oral Arg. Tr. 29:4–
7 (NIH arguing that “off topic” is a “commonly understood”
term but providing no explicit definition); id. at 29:20–21 (NIH
stating that “[t]here’s nothing in the comment guidelines that
define[s] what off topic means”); id. at 54:22–55:25 (NIH
stating its moderators use their “experience”). And without
such guidance, in this context at least, it is far from clear where
the line between off-topic and on-topic lies.
Take another recurring example from the record: An NIH
post highlighting a study by a researcher who regularly
conducts experiments on animals but did not conduct any such
experiments in the particular study highlighted. See Jt. Stip.,
Exs. 13, 17, 25, 29; Appellants’ Brief 27 n.11. One could argue
that a comment criticizing that researcher’s general use of
animal testing is on-topic, because the post introduced the
researcher as a “topic” of the post. But one could also
reasonably think that such a comment is off-topic because the
specific study highlighted is the relevant “topic,” and the study
itself did not involve animal testing. Simply announcing a rule
against “off-topic” comments does not provide “objective,
workable standards,” Mansky, 585 U.S. at 16, to guide either
NIH’s social media moderators or the public as to how to
divine “what may come in from what must stay out,” id. at 21.
Though we have never required a speech restriction to

-- 15 of 18 --

16
demonstrate “perfect clarity,” the problem with NIH’s off-topic
rule goes “beyond close calls on borderline or fanciful cases.”
Mansky, 585 U.S. at 21 (internal quotation marks omitted).
Moreover, while NIH claimed in this litigation that there was
an “alarming number of repetitive, off-topic” comments about
animal testing, Appellee’s Brief 25, NIH provided no line
(either to us or to its own social media moderators) demarcating
what is an acceptable number of off-topic posts and what is too
much.
“It is ‘self-evident’ that an indeterminate prohibition
carries with it ‘[t]he opportunity for abuse, especially where [it]
has received a virtually open-ended interpretation.’” Mansky,
585 U.S. at 21 (quoting Bd. of Airport Comm’rs of L.A. v. Jews
for Jesus, 482 U.S. 569, 576 (1987)). It is perhaps no surprise
then that NIH’s moderators originally added terms like
“PETA” and “#stopanimaltesting” to the keyword filters which
were then, during this litigation, removed once NIH realized
those terms “may have signaled a certain viewpoint.”
Defendants’ Cross-Motion for Summary Judgment 26, PETA,
No. 21-cv-2380, (D.D.C. May 6, 2022), ECF No. 31. The
district court forgave these keyword choices as “an overzealous
attempt by a NIH social media manager to tamp down
irrelevant posts.” PETA, 2023 WL 2809867, at *13 n.13. To
us, however, these missteps are confirmation that NIH’s policy
does not “guide[]” its social media managers with any
“objective, workable standards.” Mansky, 585 U.S. at 21. That
undermines the reasonableness of the NIH policy.
NIH’s off-topic policy, as implemented by the keywords,
is further unreasonable because it is inflexible and
unresponsive to context. In American Library Association, for
example, even though the pornography filters erroneously
blocked some websites that did not show pornographic content,
the Supreme Court held that the policy was reasonable in part
because library patrons could easily disable the filtering

-- 16 of 18 --

17
software by asking a librarian to unblock the site either
temporarily for their own use or permanently for use by others.
539 U.S. at 209.
By contrast, NIH’s moderation policy lacks comparable
features. The keyword filters apply automatically to comments
on all NIH posts. They do not account for the topic of any
given post or the context in which a comment is made—for
example, a long comment that is generally responsive to the
post would be filtered out if it uses any one of the keywords.
Further, NIH does not employ any manual review of comments
to restore otherwise on-topic comments that have been
removed, turn off its filters when it posts content that is likely
to make certain keywords relevant, or even routinely review its
keyword list to consider whether its keywords should be
removed (at least absent a lawsuit). See Jt. Stip. ¶ 61; Oral Arg.
Tr. 54:1–4. Users seemingly have little, if any, ability to ask
NIH to restore their comments; indeed, they typically are not
notified when their comments are filtered out. See Jt. Stip.
¶¶ 18, 34. The permanent and context-insensitive nature of
NIH’s speech restriction reinforces its unreasonableness,
especially absent record evidence that comments about animal
testing materially disrupt NIH’s ability to meet its objective of
communicating with citizens about NIH’s work.
Finally, NIH’s off-topic restriction is further compromised
by the fact that NIH chose to moderate its comment threads in
a way that skews sharply against the appellants’ viewpoint that
the agency should stop funding animal testing by filtering
terms such as “torture” and “cruel,” not to mention terms
previously included such as “PETA” and “#stopanimaltesting.”
The right to “praise or criticize governmental agents” lies at the
heart of the First Amendment’s protections, Mills v. Alabama,
384 U.S. 214, 219 (1966), and censoring speech that contains
words more likely to be used by animal rights advocates has
the potential to distort public discourse over NIH’s work. The

-- 17 of 18 --

18
government should tread carefully when enforcing any speech
restriction to ensure it is not viewpoint discriminatory and does
not inappropriately censor criticism or exposure of
governmental actions. See Ridley v. Mass. Bay Transp. Auth.,
390 F.3d 65, 86 (1st Cir. 2004).
For all of these reasons, we hold that NIH’s off-topic
restriction, as currently presented, is unreasonable under the
First Amendment. We therefore do not separately address
whether the specific keywords used to implement the off-topic
rule are, by themselves, viewpoint discriminatory.
III
The judgment of the district court is reversed, and we
direct entry of summary judgment in favor of the appellants.
So ordered.

-- 18 of 18 --