How has the Supreme Court interpreted the Second Amendment? Heller, Bruen, and the historical tradition test

The constitutional text of the Second Amendment is brief: 'A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.' Ratified December 15, 1791 as the second of the ten Bill of Rights amendments, the amendment has two grammatical components that generated more than a century of interpretive controversy. The prefatory clause -- 'A well regulated Militia, being necessary to the security of a free State' -- announces a purpose. The operative clause -- 'the right of the people to keep and bear Arms, shall not be infringed' -- states the right. The central interpretive dispute was whether the prefatory clause limited the operative clause to a collective right tied to militia service, as many lower courts had held, or whether the operative clause stated an individual right independent of any militia connection, with the prefatory clause merely announcing one purpose among others. The Supreme Court settled that dispute in District of Columbia v. Heller, 554 U.S. 570 (2008). Justice Scalia, writing for a 5-4 majority (Chief Justice Roberts and Justices Kennedy, Thomas, and Alito joining), held that the Second Amendment protects an individual right to possess firearms for traditionally lawful purposes such as self-defense within the home, independent of any service in an organized militia. The prefatory clause announces a purpose -- ensuring a well-regulated militia -- but does not limit the scope of the operative clause's protection of an individual pre-existing right. The Court relied on the grammatical structure of the amendment, contemporaneous commentary from the founding era, and the meaning of the phrase 'keep and bear Arms' in contexts of individual as well as collective use. Justice Stevens's dissent, joined by Souter, Ginsburg, and Breyer, argued that the prefatory clause limits the right to militia-related purposes and that the historical record supports a collective rather than individual reading.

Heller struck two District of Columbia laws: a provision that effectively banned handguns by forbidding registration of handguns after 1976, and a separate requirement that lawfully owned firearms kept in the home be stored unloaded and disassembled or fitted with a trigger lock. The handgun ban was unconstitutional because handguns are in common use for self-defense -- the core purpose the amendment protects -- and the government cannot ban the most popular category of arms citizens use for lawful purposes. The trigger-lock and disassembly requirement was unconstitutional as applied to a handgun kept for self-defense in the home because it made the firearm inoperable for the very purpose the amendment protects. Heller also set out a list of regulatory measures described as 'presumptively lawful': prohibitions on possession by felons and the mentally ill; laws forbidding the carrying of firearms in sensitive places such as schools and government buildings; laws imposing conditions and qualifications on the commercial sale of arms; and prohibitions on carrying dangerous and unusual weapons. These categories were identified without a comprehensive rationale, and subsequent litigation has turned heavily on how courts apply them. McDonald v. City of Chicago, 561 U.S. 742 (2010), extended Heller's individual right to state and local governments. The case arose from Chicago's handgun ban enacted in 1982. Because Heller addressed the District of Columbia -- a federal enclave governed directly by federal law -- the question remained open whether states were bound by the Second Amendment. Justice Alito's plurality (joined by Roberts, Scalia, and Kennedy) held that the Second Amendment is incorporated against the states through the Due Process Clause of the Fourteenth Amendment. Justice Thomas concurred in the judgment but declined to rely on the Due Process Clause, arguing instead that the Second Amendment is incorporated through the Privileges or Immunities Clause of the Fourteenth Amendment and that the Slaughter-House Cases (1873) were wrongly decided in narrowing that clause's scope. The four dissenting Justices (Stevens, Ginsburg, Breyer, Sotomayor) would have declined incorporation. The Chicago ban was struck down, and after McDonald every firearm regulation in all fifty states is subject to Second Amendment scrutiny.

New York State Rifle & Pistol Association, Inc. v. Bruen, 597 U.S. 1 (2022), reshaped the legal framework for evaluating Second Amendment challenges. New York's Penal Law required applicants for an unrestricted license to carry a handgun in public to demonstrate 'proper cause' -- a particularized need for self-defense beyond the general desire common to all law-abiding citizens. Justice Thomas wrote for a 6-3 majority (joined by Roberts, Alito, Gorsuch, Kavanaugh, and Barrett; Chief Justice Roberts and Justice Kavanaugh wrote separately to note certain historical regulations may survive). The majority struck New York's proper-cause requirement, but the decision's doctrinal importance extends beyond that outcome. Bruen replaced the two-step means-ends balancing framework that most federal courts of appeals had applied after Heller -- which first determined whether challenged conduct fell within the ambit of the Second Amendment and then applied scrutiny calibrated to the severity of the burden -- with a single text-and-history test. Under the Bruen test, when the Second Amendment's plain text covers an individual's conduct, the Constitution presumptively protects that conduct. The government must then demonstrate that the challenged regulation is consistent with the nation's historical tradition of firearm regulation. To do so, the government must identify a historical analogue -- a regulation from the relevant historical period that is 'relevantly similar' to the challenged law in terms of the burden it imposes on the right and the justification it offers for that burden. For regulations addressing conduct that existed in 1791, the relevant period is primarily the founding era; for regulations addressing 'unprecedented societal concerns' or 'dramatic technological changes' -- such as regulations of modern semiautomatic weapons that did not exist in 1791 -- courts may also consult the period around the 1868 ratification of the Fourteenth Amendment. The majority disavowed interest balancing and 'nuanced levels of scrutiny,' holding that the historical inquiry is the exclusive test. Justice Breyer's dissent, joined by Sotomayor and Kagan, argued that the majority's approach ignores the practical consequences of firearm regulation and gives lower courts inadequate guidance for deciding which historical analogues are 'relevantly similar.'

United States v. Rahimi, 602 U.S. 680 (2024), was the Supreme Court's first opportunity to apply the Bruen text-and-history framework to a specific federal firearm prohibition. Zackey Rahimi had been subject to a civil domestic violence restraining order entered after he assaulted his former girlfriend and was alleged to have opened fire at a bystander who witnessed the assault. After police found firearms in his home, Rahimi was charged under 18 U.S.C. Section 922(g)(8), which prohibits possession of firearms by any person subject to a qualifying civil protective order -- specifically, an order issued after a hearing, containing a finding that the person poses a credible threat to a partner's physical safety, and explicitly prohibiting the use, attempted use, or threatened use of physical force against the partner. The Fifth Circuit had held that the statute violated the Second Amendment under Bruen because the government could not identify a direct historical analogue to a law disarming persons subject to civil domestic-violence restraining orders, which did not exist in the founding era. The Supreme Court reversed, 8-1, with Chief Justice Roberts writing for the majority. Roberts held that the Court's historical tradition inquiry looks not for a historical twin but for a historical analogue that is 'relevantly similar' -- one that imposed a comparable burden on the right to bear arms for a comparable reason. The majority identified two categories of historical laws: surety-of-the-peace statutes, which allowed magistrates to require individuals who posed a credible threat to the safety of others to post bond or surrender arms, and going-armed laws, which penalized individuals who carried arms in a manner that terrorized others. Together, those historical laws established a tradition of disarming people who posed a credible threat to the physical safety of others -- the same justification underlying 922(g)(8). Justice Thomas wrote the sole dissent, arguing that the majority's 'relevantly similar' standard is itself a form of balancing that departs from Bruen's historical method. In the same term, Garland v. Cargill, 602 U.S. 406 (2024), decided 6-3 with Justice Thomas writing, held that bump stocks -- devices that use the recoil of a semiautomatic rifle to help the shooter cycle the trigger faster -- do not convert the rifle into a 'machinegun' within the meaning of 26 U.S.C. Section 5845(b), because each shot still requires a separate function of the trigger. Cargill struck the ATF's bump stock rule on statutory grounds without reaching any Second Amendment question.

The Bruen decision and Rahimi's application of it have generated extensive lower-court litigation in the years leading up to the 2028 election, with results that remain unsettled. The federal felon-in-possession prohibition, 18 U.S.C. Section 922(g)(1), has faced as-applied Second Amendment challenges from defendants convicted of nonviolent felonies, who argue that the founding-era historical record supports disarming only persons convicted of crimes that carried death or forfeiture at common law -- not nonviolent or regulatory offenses with no historical analogue. Circuit courts have divided on this question. State and local magazine-capacity limits -- which restrict the number of rounds a detachable magazine may hold -- have been challenged on the ground that founding-era history provides no analogue to regulating ammunition feeding devices rather than firearms themselves. Assault-weapon ban statutes that prohibit semiautomatic rifles with certain features have been challenged under both Heller's 'dangerous and unusual weapons' caveat and Bruen's text-and-history standard, with courts divided on whether modern semiautomatic rifles are in 'common use' for lawful purposes -- a fact that would presumptively protect them under Heller -- or fall outside the amendment's protection as dangerous and unusual. The prohibition in 18 U.S.C. Section 922(g)(3) on firearm possession by unlawful users of controlled substances has also faced challenges under Bruen. For the 2028 presidential election, Second Amendment doctrine matters in two related ways. First, the 2028 Senate election -- all 33 Class II seats are on the ballot -- determines which party controls the chamber and which nominees to the Supreme Court and lower federal courts are confirmed; those judges will resolve the circuit splits and define the reach of Bruen's historical-tradition test for the coming generation. Second, gun policy -- background check expansion, red flag laws permitting temporary removal of firearms from individuals deemed a credible danger to themselves or others, and restrictions on assault-style weapons and large-capacity magazines -- is a major campaign issue, and the constitutional viability of any enacted policy will depend on how confirmed judges apply the Bruen framework to Second Amendment challenges.