Litigation Highlight: Split Fifth Circuit Panel Renews Injunction Against ATF’s Stabilizing Brace Rule

This guest post does not necessarily represent the views of the Duke Center for Firearms Law.

On August 1, a split Fifth Circuit panel issued a decision in Mock v. Garland that breathed new life into an emergency injunction previously granted against ATF’s recent rule on stabilizing pistol braces. (I previously blogged about the early legal challenges to that rule here.) The majority’s decision reversed the district court’s denial of plaintiffs’ motion for preliminary injunction, finding that the plaintiffs had indeed demonstrated a likelihood of success on the merits of their challenges based on the Administrative Procedure Act of 1946 (APA). Having resolved the first prong of the preliminary injunction inquiry, the majority remanded the case back to the district court to conduct the remainder of the analysis.

The reader may wonder, rightfully, ‘what impact does this have on Second Amendment doctrine, or even gun policy on the ground?’ The answer: not too much. This decision will probably receive more citations for its impact on Fifth Circuit administrative law than for anything to do with firearms, because the decision adopts a balancing test for differentiating between “legislative” and “interpretive” administrative rules. Even if you own a pistol brace, your legal rights and responsibilities remain unchanged, since Mock only has the practical effect of extending an injunction that was already in place.

But, for a few reasons, Mock is still worth examining in detail. First, so much of recent federal gun policy has been promulgated via federal agencies, not through Congress, and this trend shows no sign of abating. In fact, the same trend appears in other key areas of federal policymaking like environmental and securities law. So, it’s important for gun scholars to keep an eye on admin-heavy cases like Mock, since the decisions in those cases will have lasting impacts on the way all sort of federal laws are both enacted and enforced. Second, though Mock was decided on purely administrative law grounds, its concurrence and dissent both contain some interesting musings about Bruen and the Second Amendment. In a world where appellate opinions analyzing Bruen are still a precious commodity, the Mock dicta should not be overlooked.

To appreciate the full (in)significance of this decision, a quick tour of its procedural history will prove useful. Mock v. Garland, filed in early 2023 and docketed before Judge Reed O’Connor in the Northern District of Texas, was one of a handful of cases filed in the immediate wake of ATF’s announcement of Final Rule 2021R-08F, “Factoring Criteria for Firearms with Attached ‘Stabilizing Braces.’” The Final Rule altered the regulatory definition of “rifle” in such a way that most (if not all) pistols equipped with stabilizing braces became subject to heightened possession, registration, and taxation regulations under the National Firearms Act of 1934 (NFA) and the Gun Control Act of 1968 (GCA). (See this post for a fuller discussion of the Final Rule and the legal challenges it immediately inspired).

The plaintiffs in Mock (who include the Firearms Policy Coalition, two pistol brace owners, and the pistol brace manufacturer Maxim Defense) alleged that the Final Rule was unlawful on both constitutional grounds (concerning the First Amendment, Second Amendment, due process, and separation of powers concerns) and statutory grounds (concerning primarily the APA).

Shortly after filing their amended complaint in February, the plaintiffs moved for a preliminary injunction.  Judge O’Connor denied that motion at the end of March. In the opinion denying the injunction, Judge O’Connor concluded that the plaintiffs were not likely to succeed on the merits of any claim. The plaintiffs immediately filed an interlocutory appeal to the Fifth Circuit and moved in the district court for the judgment to be stayed pending the outcome of that appeal, but the district court did not immediately rule on the motion for a stay.

As the enforcement date of the Final Rule (May 31, 2023) approached, the Mock plaintiffs petitioned the Fifth Circuit for an emergency injunction preventing ATF from enforcing the Final Rule against the plaintiffs. That request was granted before the enforcement date arrived. The order granting the emergency injunction stated that the motion was granted only “as to the Plaintiffs in this case;” in a later order, the appellate court clarified that the injunction was effective not only with regard to the named plaintiffs themselves, but also to customers of Maxim Defense and the members of the Firearms Policy Coalition. Similar injunctions were granted by three district court judges sitting within the Fifth Circuit in other cases challenging the pistol brace rule.[1] The parties in Mock then filed briefs on an expedited schedule and argued the case before a three-judge panel in late June, consisting of Judge Jerry Smith, Judge Stephen Higginson, and Judge Don Willett. (For my summary of and impressions about the oral argument, see this thread).

After that long procedural wind-up, the Fifth Circuit panel issued its opinion on August 1. In a split 2-1 decision, Judges Smith and Willett voted to reverse Judge O’Connor’s denial of plaintiff’s motion for preliminary injunction, finding that the plaintiffs were, in fact, likely to succeed on the merits of their APA claims. Judge Willett wrote a concurring opinion expressing his concern that the Final Rule likely violated the Second Amendment in addition to the APA. Judge Higginson dissented, challenging the conclusions of both the majority and the concurring opinions. For ease of exposition, I’ll consider the APA and Second Amendment issues separately, explaining along the way where each opinion falls on the relevant issue.

APA Issues: “Legislative” vs. “Interpretive” Rules and the “Logical-Outgrowth” Test

The meat of the majority opinion began with a brief review of some of the plaintiffs’ non-APA claims: namely, challenges based on nondelegation principles and the rule of lenity (the rule might arguably apply here, since noncompliance with ATF regulations can lead to criminal prosecution). The majority expressed its opinion that those claims “may be colorable,” but declined to analyze them further, perceiving the plaintiff’s APA claims to be strong enough to satisfy the “likelihood of success on the merits” prong of the preliminary injunction analysis.

Specifically, the majority found that the Final Rule likely violates the APA’s “procedural and substantive requirements.” The logic of the Final Rule’s deficiency has two distinct prongs. First, the majority found that the Final Rule was “legislative in character” (as opposed to “interpretive”), and was therefore subject to the strictures of the notice-and-comment process. One such stricture requires any ‘Final Rule’ that emerges from the notice-and-comment procedure to be a “logical outgrowth” of the ‘Proposed Rule’ it succeeds. The majority found the Final Rule deficient on this ground because it “bears almost no resemblance in manner or kind to the Proposed Rule” that was submitted to the public for comment back in 2021.

It is worth pointing out—as the majority admitted, and the dissent stressed—that the Fifth Circuit has previously struggled to clarify the precise difference between a legislative and an interpretive rule. With this analytical “smog” in mind, the majority chose to “resolve the question” by adopting a five-factor balancing test introduced by Judge David Alan Ezra in the Cargill v. Barr case (the predecessor to the Fifth Circuit’s en banc decision in Cargill v. Garland, which nullified the Trump-era ATF “bump stock” rule). The five factors to be considered are: (1) “whether the agency intended to speak with the force of law;” (2) “whether the agency published its rule in the Code of Federal Regulations;” (3) “whether the agency ‘explicitly invoked its general legislative authority;’” (4) “whether the agency claimed Chevron deference;” and (5) “whether the rule ‘will produce [] significant effects on private interests.’”

The majority found two factors easy to resolve in Mock. First, the Final Rule was published in the CFR, suggesting that it is legislative rather than interpretive. Second, ATF did not claim Chevron deference, which suggests the Rule is interpretive. As for the other three factors, the majority found that each one weighs in favor of a finding that the Rule is legislative. In support of this conclusion, the majority pointed to the “prospective, binding language” used by ATF when describing the steps brace owners must take to bring themselves in compliance with the Rule and stressed the “significant implications” the Rule would have for brace owners, adopting the plaintiff’s assertion that “[i]f the government is correct, and the rule is only interpretive, millions of Americans were committing a felony the entire time they owned a braced pistol.”

By contrast, the dissent argued that the majority’s eagerness to “resolve the question” of what makes a rule legislative or interpretive was inappropriate in this case. Pointing out the surprising paucity of argument in the plaintiffs’ briefing dedicated to that topic—about half a page—Judge Higginson cautioned that “[j]udicial restraint strongly counsels against the creation and application of a new test, in an infamously difficult area of administrative law, in an expedited matter, without the benefit of meaningful adversarial briefing.” The dissent was especially skeptical of the test’s fifth and final factor, which asks whether the Rule in question has a “substantial impact” on the interests of the private parties that are regulated by it, on the theory that such an inquiry “tells us little about whether [a Rule] is legislative rather than interpretive” yet “inexorably answers” that question in favor of the former.

It is hard to say who has the better of this argument, both because the precedent caselaw is thorny and because, as the dissent points out, the parties didn’t brief this issue in the traditional adversarial manner. Such uncertainty can, in some cases, be rightfully seen as an invitation toward clarification; indeed, such clarification is a chief task of the circuit courts in our federal system. But, in this case, where the uncertainty has not been subjected to the caliber of informed debate befitting a fully-briefed argument before a circuit court, I am inclined to agree with Judge Higginson that the uncertainty cautions against hasty resolution.

But, at the end of the day, the distinction between legislative and interpretive Rules is not dispositive in this case. If a Rule is deemed legislative, it merely means that the rule is subject to the strictures of the notice-and-comment process laid out in the APA. In other cases, where an agency skips the notice-and-comment stage altogether, the “legislative” designation renders the Rule null; but in this case, ATF conducted the notice-and-comment procedure, so the analysis does not end there.

Instead, the additional question that the majority was most concerned with was whether or not the Final Rule was a “logical outgrowth” of the Proposed Rule. Under Fifth Circuit precedent, a Proposed Rule must “adequately frame the subjects for discussion such that the affected party should have anticipated the agency’s final course in light of the initial notice.” The majority stressed that, in this case, the Proposed Rule contained a quantitative Worksheet that allowed brace owners to calculate for themselves whether or not their braced pistol would qualify as a short-barreled rifle under the revised definition of “rifle.” By contrast, the majority argued, the Final Rule presented a “six-factor test based on almost entirely subjective criteria,” a “vaguer test” that ATF showed no signs of considering in the Proposed Rule. In the majority’s words, ATF performed a “rug-pull on the public” by making it “nigh impossible for a regular citizen to determine what constitutes a braced pistol.”

The majority also found fault in the Final Rule’s concern with “third parties’ actions, such as the ‘manufacturer’s direct and indirect marketing and promotional materials,’ and ‘[i]nformation demonstrating the likely use of the weapon in the general community,’” both because the Proposed Rule did not contain those classification criteria and because they “would hold citizens criminally liable for the actions of others, who are likely unknown, unaffiliated, and uncontrollable by the person being regulated.” The majority concluded that these considerations combined to make it “relatively straightforward that the Final Rule was not a logical outgrowth of the Proposed Rule.”

By contrast, the dissent found that the Final Rule “easily [met]”  the logical-outgrowth standard (assuming arguendo that the rule is in fact legislative, which the dissent doubted). Where the majority found fault in ATF’s disposal of the proposed Worksheet, the dissent found this a shining exemplar of the benefits of the notice-and-comment process: “[t]his is a straightforward case, then, where ‘the changes reflected in the final rule were instigated by industry comments,’ indicating that ‘the final rule was a logical outgrowth of the comments received.’” To illustrate, the dissent pointed to several comments submitted in response to the NPRM, including one submitted by the plaintiff Firearms Policy Coalition, which lamented the Worksheet’s “highly subjective,” “malleable,” and “indeterminate” factors and warned that “such open-ended discretion renders the proposed criteria/factors meaningless.” For Judge Higginson, “the complaints raised in this litigation were fully aired in comments to the agency. This is a meaningful indicator that the notice-and-comment requirement was satisfied.” “And even if the Final Rule is… ‘more subjective and ... less consistent’ than the Worksheet,” the dissent concluded, “that does not mean that the proposed rule did not provide adequate notice under the APA.”

The majority ends its opinion by remanding the case to Judge O’Connor to complete the remainder of the preliminary injunction analysis (i.e., whether the plaintiffs can show irreparable harm, and whether the balance of equities and the public interest favor a preliminary injunction). Notably, the majority declined the plaintiffs’ plea to “conduct this analysis ourselves and enter a nationwide injunction,” in part because “the district court has not conducted extensive fact-finding or built a record” robust enough to support the requested relief. It is interesting to note that the majority nonetheless found the same record and pleadings “extensive” enough to support the adoption and application of Judge Ezra’s Cargill test, despite somewhat paltry briefing on the topic of the legal distinction between legislative and interpretive Rules and despite the fact that portions of the Cargill test ask questions similar to the preliminary injunction analysis (i.e., the size and type of harm incurred by the regulated parties). The dissent emphasized this point too, reminding the reader “that Judge O’Connor is free to go in any direction, including limiting any injunctive relief to an appropriately narrow scope, or finding that the balance of equities favors issuing no injunction at all.” Finally, the majority extended the emergency injunction it had previously granted until 60 days from August 1 or until the district court rules anew on the preliminary injunction motion, whichever happens first.

Second Amendment Speculation: Bruen’s Flexibility and Footnote 9

As I mentioned earlier, even though this case was decided on APA grounds, Judge Willett wrote a separate opinion speculating that the Final Rule may also violate the Second Amendment. Although this concurrence lacks the force of law and isn’t strictly germane to the fate of the pistol brace in America (at least, not at this stage), it is worth briefly exploring Judge Willett’s arguments and Judge Higginson’s responses to them, if for no other reason than to gain an insight into how these prominent appellate judges are thinking about concerns left unresolved by Bruen.

One concern that has repeatedly provoked the commentariat is the apparent flexibility with which judges and litigants can characterize the input data that fuel the Bruen test: namely, the activities purportedly protected by the Second Amendment (at Step One), and the examples of analogous regulation from our nation’s history (at Step Two). Take Judge Willett’s concurring opinion as an example, which characterized the pistol brace as a device designed to improve a pistol user’s stability, and thus their accuracy. For this reason, he considered the “conduct” relevant to the Bruen test as the “making [of] common, safety-improving modifications to otherwise lawfully bearable arms.” If that is the conduct at issue, then in order to validate a regulation that restricts such modifications, per Judge Willett, the government would have to demonstrate a historical tradition of “requiring ordinary citizens to endure a lengthy, costly, and discretionary approval process just to use accessories that make an otherwise lawful weapon safer.”

In comparison, consider Judge Higginson’s dissent, which argued that “stabilizing braces are functionally equivalent to shoulder stocks,” and therefore pistols equipped with braces are “uniquely dangerous because they ‘combine the power of shoulder-mounted rifles with the concealability of handguns.’” The relevant conduct, per Judge Higginson, is not the safety-improving modifications that Judge Willett imagines, but rather the possession of an unusually dangerous weapon, which has long been regulated throughout American history and is therefore presumptively constitutional under Bruen.

For the sake of this discussion, it doesn’t matter whose version of the story you find more plausible—what’s important is the fact that two federal appellate judges, sitting side by side on the same panel and briefed with identical materials, can arrive at literally opposite characterizations of the same conduct for the sake of the Bruen analysis. The fact that a relatively young Supreme Court doctrine may be applied in manifold (and even opposing) ways is, of course, neither new nor unique to the Second Amendment. But the large amount of judicial wiggle room inherent in the text-and-history test arguably gives the lie to Justice Thomas’s claims in Bruen that eliminating “judge-empowering” means-end scrutiny from Second Amendment doctrine will restrain judicial activism or selective judging. Indeed, we can see in these supplemental Mock opinions a clear example of how the test handed down in Bruen is flexible enough to accommodate diametrically opposed outcomes. Part of the neat opposition between the concurrence and dissent in Mock trades on the paradoxical fact that accurate guns are both more dangerous (à la Higginson) and less dangerous (à la Willett) than less accurate guns—depending, of course, on who wields them—but I think the point stands even in other contexts. Recall the recent en banc decision from the Third Circuit, Range v. Atty. General, where several appellate judges disagreed in good faith over whether a federal statute disarming felons should be adjudged against a historical tradition of laws disarming non-law-abiding citizens, disloyal citizens, dangerous citizens, or some other class entirely. Commentators noticed the problem of Bruen’s pliability well before Mock or Range were decided, and the passage of time will only add to the pile of cases illuminating this issue.

The last point worth flagging about the Mock opinions relates to Bruen’s footnote 9, where Justice Thomas blesses ‘shall-issue’ permitting regimes as presumptively constitutional. In his dissent, Judge Higginson likened ATF’s Final Rule (and the NFA itself) to such permitting regimes, emphasizing that the Final Rule does not actually “ban” anything. Although this point was not made directly in rebuttal to anything written in Judge Willett’s concurrence or in the plaintiffs’ complaint, it serves as a rejoinder to the claim made in other pistol brace cases that the NFA itself—insofar as it regulates short-barreled rifles, at least—is unconstitutional on Second Amendment grounds.

Judge Higginson’s point strikes me as plausible, though not entirely convincing. Since the NFA is not a total ban on the possession of certain weapons (even if it was intended to function as one when it was enacted), I think he is right in claiming that it resembles a shall-issue permitting regime more closely than, say, an assault weapons ban. But characterizing the NFA as similar to a constitutional permitting regime does not automatically foreclose Second Amendment challenges—footnote 9 itself recognizes that even a shall-issue permitting regime could be abused to an unconstitutional degree. I doubt the Final Rule rises to that level, but it’s possible that other elements of the NFA could, such as the severe criminal sanctions that the NFA establishes for non-compliance with its regulations. But importantly, if Judge Higginson is right that the NFA is presumptively lawful, then a future litigant challenging some element of the NFA on its face would likely have to plead a special kind of harm—one that rises to the level of a rights-deprivation—as opposed to simply asserting that their proposed course of conduct falls within the right guaranteed by the text of the Second Amendment.

In summary, the latest entry in the Mock v. Garland saga is probably a bigger deal for administrative lawyers practicing in the Fifth Circuit and pistol brace owners than it is for Second Amendment scholars or gun policy wonks. ATF’s pistol brace rule remains enjoined but, if notice-and-comment deficiencies are all that is wrong with the Final Rule, then I think this case is best understood as a growing pain in the modern era of gun-policy-by-rulemaking rather than some slam-dunk for gun rights groups (even if the pistol brace emerges unregulated at the end of the day). Indeed, the most interesting part about this case is probably the stuff that isn’t even law—namely, the Second Amendment musings from Judges Willett and Higginson. Their opposing perspectives offer a convenient example of how constraining Bruen’s test really is (answer: not very), a fact which seems to bother neither judge but which nonetheless casts doubt on Bruen’s status as a guarantor of judicial restraint. And both opinions weigh in on the constitutionality of the NFA itself, an issue that will almost surely make it to the courts soon. When that day comes, it’s not inconceivable that the supplemental Mock opinions will prove more influential than mere dicta.

[1] Those cases are Second Amendment Foundation v. ATF, 3:21-cv-00116 (N.D. Tex.); Britto v. ATF, 2:23-cv-00019 (N.D. Tex.); Texas v. ATF, 6:23-cv-00013 (S.D. Tex.). Each case was subsequently placed on hold pending the outcome of the Mock appeal, but no case appears to have resumed proceedings despite the appeal’s resolution.