Yang Liu was a Criminal Law Fellow, U.S. District Court for the District of Columbia. This post is based on a presentation at our October 2024 conference on the National Firearms Act.
The regulation of firearm silencers, or suppressors, has emerged as a salient topic of scholarly discourse in recent years, particularly in relation to the public health ramifications and constitutional dimensions of such regulations. According to Occupational Safety and Health Administration (OSHA) standards, impulse noise should not exceed 140 decibels to mitigate the risk of permanent auditory damage. The majority of firearms, especially larger rifles and pistols, produce noise levels that substantially exceed this threshold, often reaching levels above 175 decibels without the use of a silencer. This poses a significant health hazard, particularly for individuals regularly exposed to firearm discharge.
Although some advocate for the use of traditional hearing protection devices, such as earplugs, as an alternative to silencers, empirical evidence suggests that these measures are frequently inadequate. For instance, a study involving Finnish military personnel revealed that earplugs often fail to provide sufficient protection due to improper fit, thereby diminishing their efficacy. Moreover, earplugs can impede effective communication among individuals, hinder the detection of critical environmental cues such as wildlife sounds, and compromise the ability to hear range commands. Collectively, these limitations underscore the inadequacies of earplugs as a comprehensive solution for mitigating firearm noise exposure.
Historically, concerns regarding the potential misuse of silencers in criminal activities have prompted several states to impose stringent regulations or outright bans on civilian ownership. However, as public understanding of silencer technology has evolved, the purported nexus between silencers and criminal conduct has proven tenuous. Consequently, numerous states have relaxed their restrictions on silencer ownership over the past decade. Since 2010, states such as Maine, Michigan, Minnesota, and Vermont have revised their statutes to permit civilian ownership of silencers, thereby reversing previous prohibitions. Likewise, states including Louisiana, North Carolina, Pennsylvania, Arizona, and Wyoming have rescinded bans on the use of silencers for hunting, acknowledging that such restrictions were largely unjustified.
At present, the majority of states in the United States permit both the possession and lawful use of silencers, contingent upon registration in accordance with the National Firearms Act (NFA). Despite the persistence of certain regulatory burdens, such as the requirement for Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) approval for each interstate transport of a silencer, the prevailing trend has been towards more permissive policies that recognize both the health benefits of silencer use and the significance of Second Amendment rights.
Nevertheless, residents in eight states—including California,[1] Delaware,[2] Hawaii,[3] Illinois,[4] Massachusetts,[5]New Jersey,[6] New York,[7] and Rhode Island[8]—as well as the District of Columbia,[9] remain prohibited from legally owning silencers. In Connecticut, ownership is permitted; however, the use of silencers for hunting remains unlawful. In my research, I critically examined these state-level restrictions and posited that they likely constitute violations of the constitutional rights enshrined in the Second Amendment. Such prohibitions not only undermine individuals’ capacity to safeguard their hearing health but also appear incongruous with the broader legislative trend that increasingly acknowledges silencers as a legitimate instrument for firearm safety and effective noise management.
Under the Supreme Court’s Bruen test, courts must consider two questions to determine the constitutionality of such laws: first, does the law fall within the scope of the Second Amendment? Second, is the law consistent with this nation’s historical tradition of firearm regulation?
Regarding the first prong of the Bruen test, there is currently no Supreme Court precedent that directly addresses the constitutional status of silencers under the Second Amendment. The only relevant circuit-level precedent comes from the Tenth Circuit. In UnitedStates v. Cox, decided in 2018, the Tenth Circuit Court of Appeals held that silencers are not protected by the Second Amendment. Relying on two eighteenth-century dictionaries and one from the nineteenth century, the Court argued that silencers do not fit within the founding-era definition of an “Arm.” According to these sources, the term “Arm” refers to “[w]eapons of offense, or armor of defense,” or “anything that a man wears for his defense, or takes into his hands, or uses in wrath to cast at or strike another.” Based on this definition, the Court concluded that a silencer, as it is neither a weapon nor defensive armor, should be classified as a firearm accessory rather than an Arm. While this initial reasoning appeared sound, the Court subsequently concluded that firearm accessories are categorically unprotected by the Second Amendment. In reaching this conclusion, the Court quoted District of Columbia v. Heller, in which Justice Scalia wrote that “the Second Amendment extends, prima facie, to all instruments that constitute bearable arms.” The Tenth Circuit, however, appears to interpret this statement as implying that “only instruments that constitute bearable arms are protected under the Second Amendment.” This is not what the Hellermajority actually held; it is overly simplistic and even problematic.
First, this interpretation overlooks the broader application of the Second Amendment to firearm accessories. A prime example of this inconsistency is evident in the Garland v. Cargill case, which the Supreme Court decided earlier this year. Although Garland focused on statutory interpretation rather than the Second Amendment, the Court acknowledged that accessories, such as bump stocks, are indeed entitled to protection. This decision highlights the flaw in the Tenth Circuit’s rigid dichotomy between firearms and accessories, wherein only the former are deemed worthy of protection.
Second, the Supreme Court has long held that recognizing a fundamental right often entails protecting associated or ancillary rights that facilitate the exercise of the primary right. For example, in Griswold v. Connecticut, the Court recognized the right to privacy as a fundamental right, even though it is not explicitly enumerated in the Constitution. Justice William O. Douglas, writing for the majority, explained that several amendments—including the First, Third, Fourth, and Ninth—collectively establish “zones of privacy” that protect individuals from unwarranted government intrusion.
This reasoning logically extends to the Second Amendment. If the right to bear arms is recognized as fundamental, it follows that this right includes protections for firearm accessories, such as silencers, which facilitate and enhance the lawful use of firearms. The Second Amendment was not solely intended to protect firearm possession but also to ensure that individuals could effectively use those firearms for self-defense, hunting, and other lawful activities. Excluding silencers from this protection would force individuals to choose between safeguarding their hearing and fully exercising their Second Amendment rights—an outcome that undermines the fundamental purpose of the Amendment.
Assuming that silencers fall within the ambit of Second Amendment protection, the analysis then proceeds to the second prong of the Bruen test: determining whether historical regulations impose a comparable burden based on a comparable justification. To address this inquiry, it is pertinent to briefly review the history of silencer regulation.
Silencers were invented by engineer Hiram Percy Maxim in the early 1900s and patented in 1908. They quickly became the target of restrictive legislation in some states, driven by largely unfounded concerns linking them to organized crime and poaching—concerns that have since been largely discredited. Beginning with Maine’s total prohibition on silencer ownership on March 24, 1909, just one year after the silencer was patented, several states—though a minority—began enacting silencer restrictions. Enacted in 1934, the NFA introduced a registration-based rather than prohibition-based regulation, and suddenly halted this trend. By 1934, however, sixteen states and the District of Columbia had already introduced regulations, with eleven of them imposing outright bans (Maine,[10] Vermont,[11] Minnesota,[12]New York,[13] Massachusetts,[14] Rhode Island,[15] District of Columbia,[16] California,[17] Hawaii,[18] New Jersey[19], Michigan[20]) and others restricting their use specifically in hunting (Connecticut,[21] Louisiana,[22]Wyoming,[23] Pennsylvania,[24] North Carolina,[25] Delaware[26]).
The pertinent inquiry then is whether these pre-NFA silencer restrictions can be considered comparable historical regulations capable of justifying current prohibitions. It is true that many of the pre-NFA restrictions share striking similarities with today’s laws. Indeed, seven of the eight existing state silencer bans originated during that era and remain largely unchanged. Similarly, Connecticut’s restriction on using silencers for hunting dates back to this period and mirrors similar prohibitions across other states.
However, the Bruen Court made it clear that merely recognizing these historical similarities is insufficient. The inquiry must go further. The Court emphasized that historical regulations must align with a broader national tradition to be constitutionally relevant. In Bruen, the Court pointed to cases like Texas’s 1871 prohibition on carrying firearms without reasonable fear of attack, labeling such laws as “outliers.” These outliers, according to the Court, did not reflect a longstanding national tradition.
In assessing whether a law is representative rather than an outlier, Bruen identifies three key factors. First, the law should not represent a “legislative improvisation” typical of frontier territories that permitted extraordinary government actions at odds with the nation’s established approach to firearm regulation. Second, it must have undergone meaningful judicial scrutiny grounded in correct constitutional interpretation. Finally, the law must have existed for a sufficiently long duration.
In evaluating these factors, it is evident that the second factor decisively argues against these bans. These pre-NFA laws did not undergo any substantial judicial scrutiny, let alone judicial review grounded in a faithful interpretation of the original meaning of the Second Amendment. However, the third factor does support treating pre-NFA bans as a valid reference point, as these laws—though mostly repealed—remained in force for a considerable period, often lasting until the 2010s. This distinguishes them from the shorter-lived outliers that Bruen considered, which typically lasted only a few years to a few decades.
The critical question, then, lies in the first factor: whether these pre-NFA restrictions can be considered “legislative improvisations.” I argue that they are. To be sure, unlike the regulations discussed in Bruen, none of the pre-NFA silencer regulations were inconsistent with any existing federal laws. However, this difference primarily stems from the fact that silencers were a novel invention, and there was simply no established regulatory tradition. In a federalist system, states often lead the way in addressing emerging issues—such as those posed by novel technologies—serving as laboratories for legal experimentation. However, just because states often take the lead in regulating new technologies does not mean that these new technologies fall outside the Constitution’s protection. In cases such as Caetano v. Massachusetts, the Supreme Court has made it clear that the Second Amendment protects not only firearms that existed during the founding era but also modern innovations like stun guns.
More broadly, one of the main reasons why the Bruen Court rejected means-end scrutiny in favor of a historical test was that a longstanding national tradition offers a more reliable guide to the Second Amendment’s “origins and continuing significance.” Blindly importing state-level regulatory experiments that lack meaningful judicial scrutiny into this historical analysis will not only fail to bolster this goal, but will also undermine it. It risks diluting the Second Amendment’s importance by treating experimental state regulations—which may or may not accurately reflect the original understanding of the Constitution—as if they provide genuine historical precedent.
A closer examination of historical silencer regulations, particularly the trajectory of federal and state management, reveals that these pre-NFA era restrictions align more closely with the “legislative improvisations” described in Bruenthan with a genuine, longstanding tradition of silencer regulation within this nation. While a minority of states did impose silencer restrictions before 1934, it is notable that following the passage of the NFA, very few states pursued additional silencer regulations. The establishment of the NFA’s registration-based federal approach effectively halted the trend of state-level silencer legislation. There are only a few outliers, such as Delaware, which expanded a preexisting hunting ban into a total silencer prohibition in 1937,[27] and Arizona, which imposed a ban on silencers for hunting in 1936,[28]though this was subsequently repealed in 2012. The abrupt halt in state-level regulation after the NFA’s implementation suggests that, even if there were valid concerns about silencers being linked to organized crime, the federal registration system established by the NFA was considered and proven sufficient. In fact, the NFA has served as a reference point for the few states that chose to strengthen silencer restrictions after 1934. Connecticut, for instance, has maintained its hunting ban on silencers since 1917 but enacted additional regulations in 1976.[29] However, these regulations did not criminalize silencer possession outright, as pre-NFA approaches did. Instead, they penalized the possession of unregistered silencers under the NFA framework.
Accordingly, whether the NFA’s regulatory model or the largely laissez-faire approach of most other states better represents this nation’s historical approach to silencer regulation—or maybe both could be considered representative—it is at least evident that the NFA’s registration-based approach, supported by judicial validation, more accurately reflects a national tradition of firearm regulation consistent with the original meaning of the Second Amendment when compared to the pre-NFA silencer bans that are analogous to today’s restrictions in the few aforementioned states. And these isolated and untested silencer bans, enacted by states prior to the NFA’s adoption, are more accurately characterized as “legislative improvisations” under Bruen.
In conclusion, after considering the principles outlined by the Bruen Court, my research concludes that the NFA represents the most stringent form of silencer regulation that might be justifiable under Second Amendment jurisprudence. And current state laws that ban silencer possession or use impose an unconstitutional and excessive burden, one that is inconsistent with this nation’s historical tradition of firearm regulation.
[1] Cal. Penal Code § 33410-15.
[2] Del. Code Ann. tit. 11 § 1444, Del. Code Ann. tit. 7, § 710.
[3] Haw. Rev Stat. § 134-8 and § 134-11.
[4] 720 ILCS 5/24-1(a)(6); 520 ILCS 5/2.33(s).
[5] Mass. Gen. Laws Ann. ch. 269, § 10A.
[6] N.J. Stat. Ann. § 2C:39-3(c); N.J. Stat. Ann. § 23:4-13.
[7] N.Y. Penal Law § 265.02(2); N.Y. Env. Law § 11-0931.
[8] R.I. Gen. Laws § 11-47-20.
[9] D.C. Code § 22-4514.
[10] Act of Mar. 24, 1909, ch. 129, 1909 Me. Laws 141 (1909).
[11] Act of Nov. 14, 1912, no. 237, 1912 Vt. Acts & Resolves 310 (1912).
[12] Act of Mar. 13, 1913, ch. 64, §§ 1-4, 1913 Minn. Laws 55 (1913).
[13] Act of Apr. 6, 1916, ch. 137, § 1, 1916 N.Y. Laws 338, 338-39 (1916).
[14] Act of Apr. 16, 1926, ch. 261, 1926 Mass. Acts 256 (1926).
[15] Act of Apr. 22, 1927, ch. 1052, § 8, 1927 R.I. Pub. Laws 256, 259 (1927).
[16] July 8, 1932, 47 Stat. 654, ch. 465, § 14 (1932).
[17] 1933, Session Law ch. 39, Assembly Bill No.3 (1933).
[18] Act of July 1, 1933, no. 36, 1933 Haw. Sess. Laws 38, 38-39 (1933).
[19] Act of Apr. 7, 1911, ch. 128, § 1, 1911 N.J. Laws 185 (1911).; Act of Mar. 30, 1927, ch. 321, § 13, 1927 N.J. Laws 749 (1927).
[20] Act of May 7, 1913, no. 250, 1913 Mich. Pub. Acts 472 (1913).; 1927 Mich. Pub. Acts 888-89, An Act to Regulate and License the Selling, Purchasing, Possessing and Carrying of Certain Firearms, § 3 (1927).
[21] Act of Apr. 10, 1917, ch. 105, 1917 Conn. Laws, 2301 (1917).
[22] Act of July 3, 1918, no. 88, § 3, 1918 La. Acts 131, 132 (1918).
[23] § 97, ch. 83, 1921 Wyo. Sess. Laws 112-13 (1921).
[24] Act of May 24, 1923, no. 228, § 704, 1923 Pa. Laws 359, 386 (1923).
[25] Act of Mar. 7, 1925, ch. 460, § 4, 1925 N.C. Sess. Laws 529, 530 (1925).
[26] Act of Mar. 29, 1927, ch. 169, 35 Del. Laws, 516 (1927).
[27] Act of May 11, 1937, ch. 212, 41 Del. Laws, 657 (1937).
[28] § 1543, 1936 Ariz. Sess. Laws 204 (1936).
[29] P.A. 76-45 (1976).