In her dissenting opinion in Cargill, Justice Sotomayor offers a concession that she may come to regret down the road:
On October 1, 2017, a shooter opened fire from a hotel room overlooking an outdoor concert in Las Vegas, Nevada, in what would become the deadliest mass shooting in U. S. history. Within a matter of minutes, using several hundred rounds of ammunition, the shooter killed 58 people and wounded over 500. He did so by affixing bump stocks to commonly available, semiautomatic rifles.
One of the important Second Amendment questions that has not yet been considered at length by the Supreme Court centers around which commercially available weapons ought to be counted within the provision’s definition of “arms.” The gun-control movement insists that modern sporting rifles such as the AR-15 are sufficiently exotic as to escape protection. Second Amendment advocates, by contrast, consider such a distinction to be arbitrary, reasoning that if semi-automatic handguns are protected, then there is no reason that semi-automatic rifles aren’t, too.
Since the Heller ruling in 2008, however, this debate has been focused more on whether AR-15s are mainstream than on whether they are functionally different than other guns. This is because, as Mark W. Smith explains:
The Supreme Court’s landmark decision in District of Columbia v. Heller established the “common use” test based on the text and original meaning of the Second Amendment and under the Supreme Court’s traditional role of enforcing national, constitutional baselines against local outliers.
The Heller court established the “common use” test to decide how a court should determine whether particular objects, or arms, should be protected by the Second Amendment. Specifically, do the arms being legislated or regulated constitute arms in “‘common use’… for lawful purposes like self-defense.”
To get around this problem, those who wish to ban the AR-15 have taken to claiming that the rifle is not, in fact, “in common use,” and that, as a result, it is not protected under the Second Amendment. Remarkably, Justice Sotomayor just pulled the rug from underneath that argument — and, to make matters worse, did so in an official Supreme Court opinion on the subject of firearms law. Look, again, at the language that Sotomayor uses to describe the AR-15:
He did so by affixing bump stocks to commonly available, semiautomatic rifles.
Sotomayor even uses the word “common”! Not “everyday” or “universal” or “normal” or “usual,” but common — the very word that was used in Heller.
Naturally, I do not expect Sotomayor to remain consistent. If, in the course of a case delineating the meaning of “arms,” she is asked to decide whether the AR-15 is in common use, she will undoubtedly insist that it is not. But, by the point at which she does so, her words will have been used over and over and over again — in the amicus briefs, during oral arguments, and perhaps in the majority opinion, too.