The ball is officially in the justices’ Supreme Court on whether to decide if AR-15 bans are constitutional.

The petitioners challenging Maryland’s ban on so-called assault weapons filed their final brief asking the Supreme Court for cert on Monday. It responds to Maryland’s argument against taking the case and makes one last attempt to persuade at least four members of the Court that this term is the right time to hear an AR-15 ban case.

“Incredibly, in the sixteen years since Heller every single court of appeals to consider the question has concluded that such bans are constitutional, employing a variety of tests that are uniform only in their failure to adhere to the principles established by this Court,” the petitioners’ reply brief in Snope v. Brown reads. “Maryland asks this Court to deny certiorari to allow even more time for percolation, but enough is enough. The lower courts have proven themselves incapable of following Heller’s clear guidance, and this Court should intervene without delay.”

A day after the petitioners filed the reply brief, the Court distributed the case for its December 13 conference, where the justices will convene and decide which cases to grant and which to reject. That means the Court could issue its order on the Snope case as soon as December 16, though it could choose to re-list the case one or more times before announcing its decision. It also means that the petitioners’ arguments will be the most recent thing on the justices’ minds when doing so.

Maryland’s final brief, filed earlier this month, essentially boiled down to two basic arguments. The first is that the Fourth Circuit faithfully applied the Supreme Court’s guidance in upholding the state’s ban. The second is that it is too early for the High Court to weigh in on the matter, even if it disagrees with the first claim.

“The Fourth Circuit’s decision is faithful to Heller, Bruen, and Rahimi,” the state’s brief reads. “There is no reason why this Court should stray from its usual practice of allowing questions to percolate in multiple courts of appeals, with arguments tested and refined in cases litigated through final judgment on the merits, before granting certiorari.”

The petitioners rejected Maryland’s claim that lower courts deserve more time to develop the relevant Second Amendment caselaw surrounding hardware bans before the Supreme Court intervenes.

“Maryland has argued that this dispute is just beginning to take shape following this Court’s decision in New York State Rifle & Pistol Association, Inc. v. Bruen,” they wrote. “Nothing could be further from the truth.”

Instead, they argued that the question of whether governments can ban firearms that are “in common use by law-abiding citizens” has been an open battle since the Supreme Court decided Heller in 2008. While the petitioners contended that a straightforward reading of the Court’s Heller opinion should invalidate AR-15 bans across the board, they pointed out that federal appeals courts have unanimously ruled the other way under standards of their own creation.

“Remarkably, every circuit to confront the question has (somehow) held that whatever the test for protected arms should be, it should not be the common use test prescribed by Heller and confirmed by Bruen,” the brief reads. “In casting about for some way to sustain bans on common arms, courts have concluded that arms can be banned if they are (in the court’s estimation) ‘particularly capable of unprecedented lethality,’ ‘ill-suited and disproportionate to self-defense,’ or ‘predominantly useful in military service.'”

As a result, they argued that continuing to give the lower courts more time, as Maryland suggests, would be a lost cause and only encourage further legal obfuscation.

“The debate over whether common arms can be banned has persisted in the circuits since Heller, and this Court’s intervention is required to resolve it,” the brief reads. “There is nothing to gain by waiting to see whether additional jurists adopt Heller’s common use test or instead come up with evermore-creative ways to avoid it.”

In addition to the ripeness argument, the petitioners directly appealed to the Court’s role in superintending its past holdings. They argued allowing lower courts to ignore or alter the justices’ landmark gun rulings risks long-lasting distortions to the burgeoning field of Second Amendment jurisprudence.

“Intervention is particularly important because, in the ongoing debate below, the side that to date has always prevailed is also the side that is flouting this Court’s clear teaching in Heller,” the brief reads. “This error results in an ongoing infringement of the fundamental right to keep and bear arms in the states that have made the most popular rifle in America illegal. It also has created a doctrinal mess with far-reaching effects as courts do violence to the Bruen analytical framework to justify what should be unjustifiable.”

As an analogous example, they pointed to the development of various “interest-balancing“ tests in lower courts reviewing gun cases following Heller, even though Heller never relied on such a test. They pointed out that the interest-balancing regime continued until the Supreme Court finally weighed in again on the Second Amendment in 2022 and explicitly rejected it in favor of the text, history, and tradition test. They said a similar dynamic was now at play with arms bans that warranted an immediate cert grant.

“Following Bruen, the skewing of Second Amendment doctrine has continued, it has just been forced into other avenues,” the brief reads. “Several courts, including the Fourth Circuit below, have distorted Heller’s discussion of M-16 rifles to suggest that, contrary to the text of the Amendment itself, arms can be banned because of, not despite their utility to the military.”

They pointed out that, even beyond the Fourth Circuit’s ruling in the Snope case, other circuit courts have used this idea to suggest that AR-15s don’t count as arms under the Second Amendment.

“Something has gone awry when a court’s analysis ends with the conclusion that semiautomatic rifles are not even ‘arms,'” they concluded.

Overall, the reply brief attempts to allay some of the potential concerns the justices may have with taking an “assault weapon” ban case this term. While, in many ways, the Snope case is the best vehicle gun rights advocates have had to date for enticing the Supreme Court to strike down AR-15 bans, one of its only weaknesses as a candidate is simply the fact that it stands alone as the only post-Bruen appeals court merits ruling on such a ban.

Part of that is simply a structural disadvantage based on the geographic sorting of state-level gun bans and the ideological slant of the courts that oversee them–a factor unaddressed in the reply brief–that makes it unlikely a circuit-split will emerge on this issue anytime soon, if ever.

Though the Supreme Court generally prefers to hold off on hearing big constitutional questions until there’s an active controversy between the lower appellate courts, it isn’t a hard and fast rule. The petitioners’ arguments about the real controversy being over how lower courts have distorted Heller since 2008 could be enough to overcome that hesitance.

The Court has already heard or will soon hear two separate gun-related cases this term. Yet, it has not agreed to take up any explicit Second Amendment cases since it decided US v. Rahimi last year. We could find out sometime in December or January whether a Snope grant will soon change that.