The Tenth Circuit just granted rehearing en banc in the case of Aposhian v. Barr, a challenge to the Trump Administration’s bump stock regulation promulgated in response to the 2017 mass shooting in Las Vegas. The court has asked counsel to answer five specific questions in the briefs, including multiple fascinating inquiries related to the doctrine of Chevron deference.

Courts review agency interpretations of law according to the two-step framework set forth by the Supreme Court in the 1984 case of Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc. At step one, if “Congress has directly spoken to the precise question at issue, . . . that is the end of the matter; for the court, as well as the agency, must give effect to the unambiguously expressed intent of Congress [in the statute].” An empirical analysis of Chevron cases demonstrates that from 2003 to 2013, agencies won 38.8% of cases at this step.

If, by contrast, “the statute is silent or ambiguous with respect to the specific issue, the question for the court is whether the agency’s answer is based on a permissible construction of the statute.” This is step two of the framework, at which agencies won a staggering 93.8% of cases over the same period of time.

In Aposhian, the Tenth Circuit applied step two of the Chevron framework to uphold the Bureau of Alcohol, Tobacco, Firearms and Explosives’ (ATF) interpretation of the word “machinegun” under the National Firearms Act (NFA) as permissible. “Machineguns” are regulable under the NFA, and ATF’s interpretation of “machinegun” as encompassing bump stocks would allow the Attorney General to regulate bump stocks.

A problem: The government never asked for Chevron deference here. In fact, “the government ‘went out of [its] way to avoid citing Chevron and its progeny and repeatedly stressed that [the defendants] neither request, nor believe their interpretations are entitled to, any measure of deference.’” The only mention of Chevron came in the plaintiff’s brief, in which the plaintiff argued against its use in the case at hand. No matter—the appellate court applied Chevron anyway to find in the government’s favor.

Is that appropriate? It remains to be seen; one of the five questions that the court put forward for en banc review is as follows: “Does Chevron step-two deference depend on one or both parties invoking it, i.e., can it be waived; and, if it must be invoked by one or both parties in order for the court to apply it, did either party adequately do so here?”

When he was on the Tenth Circuit, then-Judge Gorsuch lamented the practice of deferring under Chevron in cases in which the government does not request such deference. Dissenting from a panel opinion that applied Chevron when the only party to raise it was the plaintiff in a footnote, then-Judge Gorsuch wrote, “We don’t normally make arguments for litigants (least of all administrative agencies), and I see no reason to make a wholly uninvited foray into step two of Chevronland.”

The majority in Aposhian countered that the plaintiff, by citing Chevron, “provided an ‘invitation’ to apply both steps of the Chevron framework.” Moreover, although the Tenth Circuit had previously noted that the court “need not” apply Chevron when the agency claims no entitlement to deference, the Aposhian panel explained that “need not” does not mean “may not.”

So, what to make of the question presented on this issue? Must a party invoke Chevron deference to get the court to apply it? Here we run into a chicken-and-egg problem: What came first, the invocation of the Chevron framework or the application of the Chevron framework? The answer, quite clearly, is the latter; the relevant citation here is Chevron itself. In the Chevron case, the government could not have invoked Chevron deference, because “Chevron” deference did not yet exist. Nevertheless, the Supreme Court applied the Chevron framework in Chevron . . . after creating it.

Perhaps, then, the better question is whether the government has recited in its brief the key elements of Chevron step two: the statute is ambiguous, the agency has made a reasonable interpretation, and the court should defer. That is what the Solicitor General argued in the government’s brief in the Chevron case itself. By contrast, the plaintiff in Aposhian said no such things. And here, ATF’s position is that the statute is not ambiguous. Therefore, if recitation of the elements (as opposed to citation of the case name) was the necessary trigger, Chevron would not apply in Aposhian.

If the en banc court disagrees, however, and finds that mere mention of Chevron—even if only in some future plaintiff’s brief—invites the framework’s application, it seems that a preemptive Chevron citation in any form or fashion by the plaintiff in a brief would become akin to playing a game of Russian roulette, except with a gun that fires a bullet 77.3% of the time. But if the plaintiff’s opening brief does not discuss Chevron, and the government invokes Chevron in a response brief, then the plaintiff’s entire discussion of Chevron—now a necessary inclusion—would be confined to the limits of its reply brief. This state of affairs would be a difficult Catch-22 for plaintiffs.

What the court has here is, in fact, a Chevron Step Zero problem. Professor Cass Sunstein analyzed the concept of Chevron Step Zero in a 2006 law review article, describing Step Zero as “the initial inquiry into whether the Chevron framework applies at all.” The quibbling about what to do if the italicized word “Chevron” appears in any of the briefs seems to evade the more important question: Should courts analyze certain agency interpretations of law under Chevron sua sponte?

When viewed through that lens, the presence or lack of a random Chevron-citing footnote in a plaintiff’s brief becomes inconsequential; instead, the court itself would simply ask whether Chevron is the appropriate framework for the case at hand, much like it would independently determine whether a party has standing or the court has subject matter jurisdiction. And to answer the Chevron question in Aposhian, the court would need to consider a bigger issue, addressed in another of the en banc court’s inquiries: “Is Chevron step-two deference applicable where the government interprets a statute that imposes both civil and criminal penalties?”

Still, one must consider the implications of implementing sua sponte Chevron review in an adversarial system, as then-Judge Gorsuch warned against doing. Looking to the history of Chevron itself, it seems that citation of the case should be secondary to the recitation of the framework’s elements when considering whether to apply the analysis. And if an agency chooses not to invoke Chevron, perhaps the court should think about why the government is choosing to forgo usage of one of the administrative state’s most powerful weapons. Sua sponte Chevron amounts instead to reflexively firing that weapon on the government’s behalf, when empirical analysis demonstrates that an agency does not need a court putting its “thumb on the scale,” as Justice Gorsuch has put it, in favor of upholding regulations.

Eli Nachmany is a second-year law student at Harvard Law School. Prior to law school, Nachmany worked in the White House Office of American Innovation as a domestic policy aide and as the Speechwriter to the U.S. Secretary of the Interior.