The Second Amendment to the United States Constitution, ratified on 15 December 1791 as part of the Bill of Rights, reads: “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.” It is among the most litigated and publicly debated provisions of the Constitution, touching on questions of individual rights, state authority, public safety, and the original intent of the founding generation.

The amendment was drafted during a period in which many Americans held deep suspicions of standing armies and viewed an armed citizenry as a safeguard against tyranny. Its text contains two clauses - a prefatory clause referencing the militia and an operative clause affirming the right to keep and bear arms - whose relationship to each other has been the central interpretive dispute in both legal scholarship and judicial decisions. For a detailed account of the amendment's origins and judicial history, see Second Amendment - History.

The Supreme Court of the United States has issued several landmark rulings bearing on the Second Amendment's scope. In District of Columbia v. Heller (2008), the Court held for the first time that the Second Amendment protects an individual right to possess firearms independent of service in a militia, at least for self-defense within the home. In McDonald v. City of Chicago (2010), the Court incorporated that right against the states via the Fourteenth Amendment. In New York State Rifle & Pistol Association v. Bruen (2022), the Court established that firearms regulations must be consistent with the nation's historical tradition of firearm regulation, shifting the analytical framework away from interest-balancing tests used by lower courts.

Despite these rulings, significant legal questions remain unsettled, including the permissible scope of regulations on particular categories of weapons, background check requirements, restrictions on who may possess firearms, and the extent to which public carry may be regulated. Federal circuits have reached differing conclusions on many of these questions.

There is legal scholarly consensus that Heller recognized an individual right, though scholars dispute its breadth and the proper method for adjudicating regulations under it. No broad consensus exists among legal scholars, historians, or public policy researchers on most contested questions regarding scope and permissible regulation.

Individual rights, broad interpretation: Some hold that the Second Amendment protects a robust individual right to keep and bear a wide range of arms with minimal government interference, and that most modern firearms regulations are constitutionally suspect. See Viewpoint: Individual Rights - Broad-viewpoint.

Individual rights, regulated: Others accept Heller's individual-right holding but argue the amendment permits substantial regulation consistent with public safety goals, including restrictions on certain weapon types, magazine capacity, and background check requirements. See Viewpoint: Individual Rights - Regulated-viewpoint.

Collective or militia-based right: Some legal scholars and advocates maintain that the amendment was primarily intended to protect the states' ability to maintain militias and does not confer a meaningful individual right to possess firearms outside that context. This view was largely rejected by the Heller majority but retains defenders in legal academia. See Viewpoint: Collective Right-viewpoint.

Public safety priority: A related policy position holds that, regardless of constitutional text, the scale of gun violence in the United States warrants broad legislative authority to regulate firearms, and that courts should defer substantially to democratic judgments in this area. See Viewpoint: Public Safety Priority-viewpoint.

Natural rights / pre-political right: Some argue that the right to armed self-defense is a natural right that predates and exists independently of the Constitution, and that the amendment merely recognizes rather than grants it. See Viewpoint: Natural Right-viewpoint.

• Second Amendment - History
• Second Amendment - Debate
• Second Amendment - Legal Consensus
• Gun Control
• Bill of Rights
• United States Constitution
• United States of America
• District of Columbia v. Heller
• New York State Rifle & Pistol Association v. Bruen

1. U.S. Const. amend. II.
2. District of Columbia v. Heller, 554 U.S. 570 (2008).
3. McDonald v. City of Chicago, 561 U.S. 742 (2010).
4. New York State Rifle & Pistol Association, Inc. v. Bruen, 597 U.S. 1 (2022).