Bump Stocks and Machine Guns as Case Study in Textualism, Chevron, and the Ambiguity of “Ambiguity”

Textualism in statutory interpretation is, on one view (which happens to be my own) a shiny, steely, precise knife blade with a handle made of silly putty. If the text is deemed to be “unambiguous,” then textualism seems to cleanly slice through obfuscation like a scalpel, cutting away all messy questions about how to define and apply broad statutory purpose, legislative history, or judicially crafted substantive canons by instructing the judge to follow the “plain” text. The blade of textualism, however, can be deployed only if the text is “unambiguous,” and unfortunately the concept of ambiguity is the most ambiguous concept of them all.

President Trump has recently provided us law profs with an interesting example of ambiguously ambiguous statutory language, suitable for in-class problems or final exams. (Whatever its merits as an effective presidency, the Trump Administration is a gift that keeps on giving to law profs teaching statutory interpretation). He has promised to ban “bump stocks” on firearms as a response to mass shootings in Parkland, Florida and Las Vegas, Nevada.

Putting aside the question of whether such a ban would produce any discernible reduction in gun deaths, does the President have the power to ban “bump stocks”? The question turns on the meaning of a six-word phrase in the National Firearms Act of 1934, a statute enacted during the national panic about Tommy-gun toting bank robbers and gangsters (e.g., “‘Machine Gun’ Kelly”). The phrase beautifully illustrates how ambiguity about ambiguity allows judges to turn Chevron and other substantive canons on and off like a spigot, all the while ostensibly adhering to the most rigorous textualism. After the jump, my thoughts on how “sliding scale” textualism might be a better way of resolving such meta-ambiguity than the grammar wars between majority and dissenting opinions now favored by SCOTUS. [Update: For an earlier formulation and much more precise and better-defended version of what I call “sliding scale” textualism, you should read Richard Re’s Green Bag essay The New Holy Trinity].

1. Why is the National Firearms Act is ambiguously ambiguous?

26 U.S.C. Section 5845(b) defines “machine gun” covered by the statute to mean

any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun....(emphasis added)

So is a “bump stock” “designed and intended” to convert a firearm into a “weapon which shoots...automatically more than one shot...by a single function of the trigger”? These devices use the recoil power of the gun to bounce (“bump”) the shooter’s finger repeatedly up against the trigger, allowing them to shoot faster than their finger’s muscular movements would normally allow. This finger-bumping action looks “automatic[]” (the shooter’s voluntary motions do not cause the trigger to be pulled). But does this bouncing mechanism constitute a “single function of the trigger”?

One can make a textual argument on either side of the question. Since each shot of a bump-stock-equipped weapon is accompanied by a corresponding pull on the trigger, one “plain text” answer might be “no”: “more than one shot...by a single function of the trigger” means that the ratio of trigger pulls to shots must be more than 1:1. On the other hand, it is that initial voluntary motion of the finger’s pulling the trigger that starts the initial recoil of the gun that, in turn, bounces one’s finger against the trigger involuntarily, thereby causing all of the subsequent recoils and bounces that lead to rapid discharge of the firearm. Why cannot that initial voluntarily induced motion of the trigger be deemed to be a “single function of the trigger” that causes the later involuntary trigger pulls leading to “more than one shot”?

In 2010, the ATF gave an opinion letter to Slide Fire, a firearms manufacturer, stating that bump stocks were not a machine gun conversion device within the meaning of the statute, because the device would not, by itself, “automatically” produce rapid fire. Instead, for the device to cause repeated trigger pulls, “the shooter must apply constant forward pressure with the non-shooting hands and constant rearward pressure with the shooting hand.”

Is the 2010 opinion letter persuasive? Again, one sinks into the Talmudic murk of ambiguously ambiguous text. The letter assumes that a device “shoots automatically more than one shot” only if the shooter makes no voluntary decisions whatsoever to insure that continuation of the automatic fire. One could argue, however, that this sort of reasoning proves too much. Machine guns normally will not fire unless the shooter applies constant pressure to the trigger: If one drops the machine gun, it does not ordinarily continue to spew bullets by itself. By extension of ATF’s reasoning, no weapon ever sold would constitute a “machine gun,” because all machine-gun triggers require the shooter to continue some sort of voluntary action for the shooting to continue.

The ATF’s letter suggests a response to this rejoinder: According to the letter, devices covered by the statute must have “automatically functioning mechanical parts or springs” to perform “an automatic mechanical function when installed.” Although the letter does not explain why this criterion is related to the statutory language, a smart lawyer might fill in the blanks: The gun “shoots automatically more than one shot” only if the statutorily required “single function of the trigger” contains an “automatic” component, and, in ordinary English, “automatic” components must have parts that move by themselves. The gun’s recoil is not part of the bump stock, which does not move by itself. No moving parts? No “automatic” function.

Shall we go one more round of this textualist style of reasoning? Against the ATF’s letter, one might ask why “automatically” should be read to modify “single function of the trigger.” In the statute’s text, “automatically” is an adverb modifying the verb “shoots,” not the noun “function.” But the ATF might reply that the canon noscitur a sociis requires that the noun “function” be read in light of nearby words like “automatically shoots,” suggesting that the device itself must move by itself — “automatically.”

In the wake of the Las Vegas mass shooting, the ATF issued an ANPRM requesting comments on whether it should revisit its 2010 interpretation. Within 30 days, ATF received over 100,000 comments on the question.

I am inclined to say that those competing comments as well as the rival arguments outlined above suggest that the statutory language is ambiguous enough for the ATF to invoke Chevron and reverse its 2010 letter ruling. But I would also concede that a SCOTUS inclined to engage in textual hair-splitting might determine that one set of textual arguments is better than the other and write that 2010 letter into statutory stone. As Yates and Lockhart Indicate, the existence of decent textual arguments on either side of a question does not suffice, in SCOTUS’s collective mind, to justify an inference of ambiguity.

The statute here, in sum, is ambiguously ambiguous. The SCOTUS could invoke Chevron or not, depending on how finely they want to weigh competing textualist arguments. And this leads to a second question, viz....

2. Why not use “sliding scale” textualism to resolve ambiguous ambiguity?

Why not determine whether statutory text is ambiguous by looking to the extra-textual purposes of a statute? As Will Baude and Ryan Doerfler incisively note in an elegant essay on the Plain Statement Rule, “a court’s perception of what Congress is trying to say depends in large part on that court’s understanding of what Congress is trying to do.” On this view, the courts ought to determine whether the NFA “unambiguously” excludes bump stocks from the definition of “machine guns” by looking into the purpose of federal regulation of machine guns. If the practical point of the statute was to place special federal controls on weapons that fire especially rapidly, then excluding the bump stock from the statute will seem odd. This practical purpose counts as a reason to weigh against the textual arguments for a narrow reading of statutory text. Even if that textual argument for a narrow reading is a little better than its rival textual argument for a broader reading, the purpose-based argument cancels out the former, at least to the extent of allowing the court to declare the statute ambiguous enough for the agency to make the final decision under Chevron.

On this “sliding scale” view of textualism, text and purpose are weighted on a single scale, with neither having absolute lexical priority over the other. Super-clear text might have priority over murky or unimportant purpose (see, e.g., United States v. Locke), but closely matched textual arguments might be “outweighed” by super-strong purpose-based arguments, even if one textual argument were slightly better than all rival textual readings. The sliding scale throws purpose into the mix of authorities right away, to be weighed alongside them at every stage of interpretation.

Such a “sliding scale” theory has the virtue of reflecting what courts actually do (albeit not what they say they do). It also provides a way to resolve conflicts among competing textual arguments other than the absurdity of balancing fly-specking textual minutiae while ignoring obvious statutory purpose. Against the objection that text reflects interest-group bargains that could run counter to the main thrust of a statute, there is the simple rejoinder: Maybe, but maybe not. If the textual arguments on either side of a question are reasonably closely balanced, then the slight superiority of one textual argument over its equally textual rival seems like a weird way to memorialize a legislative deal. After all, one would assume that the deal-makers would not want to codify their deal-making in language requiring a degree in linguistics or familiarity with some textual corpus stored at Brigham Young University. If Justice Kagan’s secret decoder ring yields an application of the “last antecedent rule” different from Justice Sotomayor’s, then it is time to throw in the towel on text, not parse every comma and romanette with the idea that somehow smuggled into the interstices of such arcana lies a bargain that lifted the veto gates of Congress. [Update #2: Ryan Doerfler’s High-Stakes Interpretation provides a powerful defense of the idea that the standards for finding semantic clarity should vary with the pragmatic stakes — a position that he defends by citing an overlapping consensus sounding in both sound semantic and pragmatic principles. I endorse Doerfler’s idea but am indifferent to its pedigree in semantics or pragmatics, since I tend to think that the distinction is of, well, merely semantic importance].