The Second Amendment protects an individual’s right to keep and carry firearms for self-defense, but that right comes with real limits on who may own a gun, what kinds of guns are legal, where they can be carried, and how they must be bought. The rights and limits of the Second Amendment have been reshaped over the past two decades by three Supreme Court decisions and a growing wave of follow-up litigation, and the rules in any given state can shift with a single ruling.
The text itself is short: “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.”1Congress.gov. U.S. Constitution – Second Amendment For most of American history, courts and commentators disagreed about whether that language protected an individual right or a collective one tied to militia service. That question is now settled.
What the Second Amendment Protects
In District of Columbia v. Heller (2008), the Supreme Court held that the Second Amendment guarantees an individual right to possess and carry weapons in case of confrontation, independent of any militia service. The decision struck down a Washington, D.C. law that effectively banned handguns in the home and required other firearms to be kept inoperable, concluding that self-defense within the home is the core purpose the amendment protects.2Justia Law. District of Columbia v Heller, 554 US 570 (2008)
Two years later, McDonald v. City of Chicago (2010) extended that protection against state and local governments through the Fourteenth Amendment. After McDonald, no level of government in the United States can impose a blanket ban on keeping firearms in the home for lawful self-defense.3Justia Law. McDonald v City of Chicago, 561 US 742 (2010)
New York State Rifle & Pistol Association, Inc. v. Bruen (2022) took the right outside the home. The Court struck down New York’s requirement that concealed-carry applicants show “proper cause,” holding that the Second Amendment presumptively guarantees a right to bear arms in public for self-defense.4Supreme Court of the United States. New York State Rifle and Pistol Association Inc v Bruen The practical effect was to invalidate “may-issue” permitting schemes, where officials could deny licenses at their discretion, and to entrench the “shall-issue” model already used in 43 states, in which anyone who meets objective criteria such as age, a clean background check, and completion of training must be granted a license.
The Court in Heller was equally clear that the individual right is not unlimited. Nothing in the opinion, the majority wrote, should cast doubt on longstanding prohibitions on possession by felons and the mentally ill, laws forbidding firearms in sensitive places such as schools and government buildings, or laws imposing conditions on the commercial sale of firearms.2Justia Law. District of Columbia v Heller, 554 US 570 (2008) Those categories still frame most of the limits below.
How Courts Now Judge Firearm Laws
Bruen replaced the balancing test lower courts had used for a decade. Under the current standard, if the Second Amendment’s plain text covers someone’s conduct, the Constitution presumptively protects that conduct, and the government must show its regulation is consistent with the nation’s historical tradition of firearm regulation.5Congress.gov. Amdt2.6 Bruen and Concealed-Carry Licenses
The government does not need to produce an identical historical law. The Court expressly rejected the idea that a “historical twin” is required; a well-established and representative historical analogue is enough.4Supreme Court of the United States. New York State Rifle and Pistol Association Inc v Bruen In United States v. Rahimi (2024), the Court applied that approach to uphold the federal law disarming people found by a court to pose a credible threat to another person’s physical safety, confirming that modern regulations can survive if they align with the principles behind the historical tradition, even without a precise historical match.6Supreme Court of the United States. United States v Rahimi
Who Cannot Own a Firearm
Federal law under 18 U.S.C. ยง 922(g) prohibits several categories of people from possessing firearms or ammunition:7Bureau of Alcohol, Tobacco, Firearms and Explosives. Identify Prohibited Persons
- Anyone convicted of a crime punishable by more than one year of imprisonment.
- Fugitives from justice.
- Anyone currently using or addicted to a controlled substance.
- People found by a court to be mentally incompetent or committed to a psychiatric institution.
- People subject to a domestic violence restraining order protecting an intimate partner or child.
- People convicted of misdemeanor domestic violence.
- People dishonorably discharged from the military.
- People who have renounced U.S. citizenship.
- Noncitizens unlawfully in the country or admitted on a nonimmigrant visa, with narrow exceptions.
Violating these prohibitions is a federal felony punishable by up to 15 years in prison, with a mandatory minimum of 15 years under the Armed Career Criminal Act for someone with three or more prior convictions for violent felonies or serious drug offenses.8Office of the Law Revision Counsel. 18 USC 924 – Penalties
Which Weapons Are Protected, and Which Are Not
The amendment does not cover every weapon. Heller extended protection to arms in common use for lawful purposes, which placed handguns squarely within the right because they are the most popular self-defense weapon in the country. At the same time, the Court acknowledged that weapons most useful in military service, such as M-16s and other fully automatic firearms, can be banned as “dangerous and unusual” arms not in common civilian use.2Justia Law. District of Columbia v Heller, 554 US 570 (2008)
The National Firearms Act
The National Firearms Act (NFA) has regulated a specific set of weapons since 1934. It reaches machine guns, short-barreled shotguns (barrels under 18 inches), short-barreled rifles (barrels under 16 inches), silencers, destructive devices, and a catch-all category of concealable weapons known as “any other weapons.”9Legal Information Institute. 26 USC 5845(a) – Definition of Firearm Legal ownership of any of these items requires an application, an extensive background check, a $200 tax, and registration with the ATF. There is no legal path to register an unregistered NFA item that someone already possesses.10Bureau of Alcohol, Tobacco, Firearms and Explosives. National Firearms Act
Unserialized “Ghost Guns”
ATF Final Rule 2021R-05F treats a partially complete frame or receiver that can be quickly and easily made functional as a firearm. That means it must carry a serial number and be sold by a licensed dealer with a background check, closing what had been a growing route to firearms without paperwork.11Bureau of Alcohol, Tobacco, Firearms and Explosives. Summary of Final Rule 2021R-05F When a licensed dealer takes an unserialized privately made firearm into inventory, the dealer must mark it with a serial number within seven days or before selling it, whichever comes first.
Where Firearms Are Restricted
Even someone with a valid carry permit can commit a serious crime by walking into the wrong building. Heller singled out schools and government buildings as presumptively lawful firearm-free zones, and Bruen reaffirmed the “sensitive places” doctrine and added legislative assemblies, polling places, and courthouses as historically recognized examples.4Supreme Court of the United States. New York State Rifle and Pistol Association Inc v Bruen
Federal law reinforces this with the Gun-Free School Zones Act, which makes it a crime to knowingly possess a firearm on school grounds or within 1,000 feet of them. Exceptions exist for people licensed by the state where the school zone sits and for firearms that are unloaded and stored in a locked container, among other narrow situations.12Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts A permit issued in one state does not override these restrictions.
Background Checks and Purchase Rules
Every sale by a federally licensed firearms dealer runs through the FBI’s National Instant Criminal Background Check System (NICS). The dealer submits the buyer’s information, and NICS checks whether the buyer falls into any of the prohibited categories under federal law.13Federal Bureau of Investigation. Firearms Checks (NICS) Most checks clear within minutes.
Federal law does not require background checks for private sales between unlicensed individuals, though many states now impose their own requirements. That gap in federal coverage is often called the private sale loophole.
Buyers Under 21
The Bipartisan Safer Communities Act, enacted in 2022, added a deeper review for buyers under 21. NICS must contact the buyer’s state criminal history repository, juvenile justice records, mental health adjudication records, and local law enforcement. If the initial check flags possible disqualifying juvenile records, the review period extends from the standard three business days up to ten business days before the sale can proceed.14Congress.gov. Text – 117th Congress (2021-2022) Bipartisan Safer Communities Act
Traveling Between States With a Firearm
State firearm laws vary sharply, which makes interstate travel with a gun a real legal risk. The Firearms Owners’ Protection Act (FOPA) provides a federal safe-passage rule: if you can lawfully possess the firearm at both your starting point and your destination, you may transport it through states with stricter laws, provided the firearm is unloaded and neither the gun nor any ammunition is readily accessible from the passenger compartment. In a vehicle without a separate trunk, the firearm and ammunition must be in a locked container other than the glove compartment or center console.15Office of the Law Revision Counsel. 18 USC 926A – Interstate Transportation of Firearms
FOPA protection applies only during continuous travel. Overnight stops or long detours in a restrictive state can put a traveler outside the safe-passage shield, and some jurisdictions have historically been aggressive about enforcing local laws against travelers despite FOPA. The federal protection is a defense, not a guarantee against arrest.
What Is Still Being Fought Over
The Bruen framework has triggered new challenges to regulations that once looked settled. Federal appeals courts have split over whether barring 18-to-20-year-olds from buying handguns from licensed dealers is consistent with historical tradition, and that circuit split makes further Supreme Court review likely. States that responded to Bruen with new sensitive-place designations and licensing conditions are facing their own suits, with lower courts producing inconsistent rulings on how far the government can push the definition of a sensitive place.
The core is stable: individuals have a right to keep firearms in the home for self-defense, that right extends to carrying in public, and the government must justify restrictions by pointing to historical analogues rather than simply invoking a public-safety interest. The edges are moving, and the rules that apply to any particular gun, buyer, or location can change with the next decision.