The Second Amendment protects an individual right to keep and bear arms for lawful purposes like self-defense, and that right applies against federal, state, and local governments alike. Second Amendment rights are not unlimited: the government can bar certain people from owning firearms, prohibit certain weapons, and restrict where guns may be carried. The Supreme Court has spent the last two decades filling in what those limits look like, and the current rules turn on a mix of who you are, what you want to own, and where you want to carry it.
What the Amendment Actually Protects
The full text is 27 words: “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.”1Constitution Annotated. Amdt2.2 Historical Background on Second Amendment For most of American history, the Supreme Court said almost nothing about what those words meant in practice. That changed in 2008.
In District of Columbia v. Heller, the Court held that the Second Amendment protects an individual right to possess a firearm for traditionally lawful purposes such as self-defense in the home, independent of any connection to militia service.2Justia. District of Columbia v. Heller, 554 U.S. 570 (2008) The decision struck down Washington, D.C.’s blanket ban on handguns, reasoning that the government cannot prohibit an entire class of arms that Americans overwhelmingly choose for lawful self-defense.3Legal Information Institute. District of Columbia v. Heller
Two years later, McDonald v. City of Chicago extended that ruling to the states. The Court incorporated the Second Amendment against state and local governments through the Fourteenth Amendment’s Due Process Clause, striking down Chicago’s effective handgun ban.4Justia. McDonald v. City of Chicago, 561 U.S. 742 (2010) After McDonald, no city or state could simply prohibit handguns outright.
Which Weapons Are Covered
Heller established the “common use” test. The right covers weapons “in common use at the time” for lawful purposes.3Legal Information Institute. District of Columbia v. Heller Modern semi-automatic handguns and rifles qualify, given how many Americans own them. The government can still prohibit weapons that are “dangerous and unusual,” a category that historically includes military-grade machine guns and explosives.2Justia. District of Columbia v. Heller, 554 U.S. 570 (2008)
Protection is not frozen in 1791. In Caetano v. Massachusetts, the Court vacated a state ban on stun guns and reaffirmed that the Second Amendment extends to all bearable arms, including those invented after the Founding.5Justia. Caetano v. Massachusetts, 577 U.S. 411 (2016)
Who Cannot Own a Firearm
Federal law bars nine categories of people from possessing, buying, or receiving firearms under 18 U.S.C. § 922(g):6Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts
- Anyone convicted of a crime punishable by more than one year in prison, regardless of actual time served.
- Fugitives from justice.
- Current users of, or people addicted to, controlled substances.
- Anyone formally found mentally incompetent by a court or committed to a mental institution.
- People unlawfully in the United States, and most people admitted under nonimmigrant visas.
- Anyone dishonorably discharged from the military.
- Former U.S. citizens who have renounced their citizenship.
- People subject to qualifying domestic violence restraining orders.
- People convicted of a misdemeanor crime of domestic violence.
A violation is a federal felony carrying up to 15 years in prison.7Office of the Law Revision Counsel. 18 USC 924 – Penalties Licensed dealers run every buyer through the federal background check system before completing a sale.8Bureau of Alcohol, Tobacco, Firearms and Explosives. Identify Prohibited Persons
The restraining order category has procedural requirements the Supreme Court laid out in United States v. Rahimi (2024). The person must have received notice and an opportunity to be heard, the order must address threats to an intimate partner or child, and it must either include a finding of credible threat or explicitly prohibit force.9Justia. United States v. Rahimi, 602 U.S. ___ (2024) An order that skips any of those steps does not trigger the federal firearms ban.
How Courts Judge Gun Laws Today
The current test for whether a firearms regulation is constitutional comes from New York State Rifle & Pistol Association v. Bruen (2022). When conduct falls within the Second Amendment’s plain text, the Constitution presumptively protects it, and the government must prove its restriction is consistent with the nation’s historical tradition of firearms regulation.10Justia. New York State Rifle and Pistol Association Inc. v. Bruen Courts no longer weigh public safety interests against the individual right. The only question is whether the government can point to a historical analogue, typically from the Founding era or the mid-1800s, that imposed a comparable restriction for comparable reasons.
Bruen itself struck down New York’s requirement that concealed carry applicants show a special need for self-defense beyond what the general public faces. Historical practice, the Court found, did not support that kind of gatekeeping discretion.10Justia. New York State Rifle and Pistol Association Inc. v. Bruen
Rahimi softened concerns that the historical test would doom nearly every modern gun law. Upholding the federal ban on firearm possession by people under domestic violence restraining orders, the Court explained that a challenged law does not need to be a “dead ringer” for a historical regulation. It must “comport with the principles underlying the Second Amendment” and be analogous enough to historical precedents.9Justia. United States v. Rahimi, 602 U.S. ___ (2024) Historical surety laws and “going armed” statutes, which allowed courts to disarm individuals who posed a demonstrated threat, provided enough historical grounding.
Sensitive Places Where Firearms Are Restricted
Even with a strong individual right, the government can bar firearms in certain locations. Both Heller and Bruen confirmed that “longstanding prohibitions on the carrying of firearms in sensitive places such as schools and government buildings” remain constitutional.10Justia. New York State Rifle and Pistol Association Inc. v. Bruen
The clearest federal example is the Gun-Free School Zones Act, which makes it a crime to knowingly possess a firearm within 1,000 feet of a school. Exceptions exist for people licensed by the state, firearms that are unloaded and locked in a container, and certain other circumstances.6Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts Courthouses, legislative chambers, and other government buildings commonly restrict firearms under state and local law, and specifics vary by jurisdiction.
After Bruen, courts have drawn sharper lines around what counts as a “sensitive place.” The closer a location resembles spaces historically off-limits to weapons, such as courts, polling places, and seats of government, the more likely a restriction will survive. Broader designations, like entire public parks or transit systems, face tougher scrutiny because their historical analogs are weaker.
Buying a Firearm: The Background Check
Every purchase from a licensed firearms dealer runs through the FBI’s National Instant Criminal Background Check System (NICS). You complete ATF Form 4473 at the counter, the dealer transmits your information to NICS, and the system searches federal and state criminal records for disqualifying history.11Federal Bureau of Investigation. Firearms Checks (NICS) Most checks return a “proceed” or “denied” result within minutes.
When the check enters “delayed” status, federal law lets the dealer proceed with the sale if the FBI cannot complete the check within three business days, though the dealer is not required to do so.12Federal Bureau of Investigation. About NICS Some states have their own laws blocking transfers until the check is fully resolved.
Buyers under 21 face an extra layer of scrutiny under the Bipartisan Safer Communities Act, signed in 2022. NICS contacts the buyer’s state criminal history repository, juvenile justice information system, and local law enforcement to search for disqualifying juvenile records or mental health adjudications.13Congress.gov. Text – S.2938 – Bipartisan Safer Communities Act NICS has three business days to decide whether further investigation is needed; if the system flags a potentially disqualifying record, the review window extends to 10 business days before the dealer may proceed. Adult buyers follow the standard three-day timeline.
Traveling With a Firearm
State-to-state variation creates real legal risk for gun owners on the road. Federal law provides a narrow safe harbor. Under 18 U.S.C. § 926A, you may legally transport a firearm from any state where you can lawfully possess it to any other state where you can lawfully possess it, as long as the gun is unloaded and neither the firearm nor ammunition is readily accessible from the passenger compartment.14Office of the Law Revision Counsel. 18 USC 926A – Interstate Transportation of Firearms If your vehicle lacks a separate trunk, the firearm and ammunition must be in a locked container that is not the glove compartment or center console.
The protection covers transit only. Overnight stops, errands, or anything beyond passing through a restrictive state can pull you outside the safe harbor and expose you to that state’s laws. Travelers have been arrested despite claiming federal transit protection when a stop was long enough that a court found they were no longer simply transporting the firearm.
Flying With a Firearm
The TSA permits firearms in checked baggage but prohibits them in carry-on bags. You must declare the firearm at the airline ticket counter during check-in, and it must be unloaded and locked inside a hard-sided container.15Transportation Security Administration. Firearms and Ammunition Ammunition must be securely packaged and can travel in the same locked case as the unloaded firearm. You remain responsible for complying with the firearms laws of both your departure and arrival locations.
Getting Firearm Rights Back
Losing firearm rights is not always permanent, but restoration is genuinely difficult. Federal law at 18 U.S.C. § 925(c) allows a prohibited person to petition the Attorney General for relief from firearms disabilities. The applicant must show that their record and reputation indicate they are unlikely to pose a danger, and that granting relief would not be contrary to the public interest. Denials can be appealed to federal district court.16Office of the Law Revision Counsel. 18 USC 925 – Exceptions; Relief From Disabilities
There is a catch. Since 1992, Congress has included a rider in the ATF’s annual funding bill barring the agency from spending any money to investigate or act on these petitions. The statutory pathway exists on paper; the federal government does not process applications. That pushes most people looking for relief to the state level, where options vary widely. Federal law generally does not recognize state expungements or record reductions as lifting the federal prohibition. In most cases, only a full pardon from a governor or the president reliably restores federal firearms eligibility.