District of Columbia v. Heller, 554 U.S. 570 (2008), is a landmark decision of the Supreme Court of the United States. It ruled that the Second Amendment to the U.S. Constitution protects an individual's right to keep and bear arms—unconnected with service in a militia—for traditionally lawful purposes such as self-defense within the home, and that the District of Columbia's handgun ban and requirement that lawfully owned rifles and shotguns be kept "unloaded and disassembled or bound by a trigger lock" violated this guarantee.. It also stated that the right to bear arms is not unlimited and that certain restrictions on guns and gun ownership were permissible. It was the first Supreme Court case to decide whether the Second Amendment protects an individual right to keep and bear arms for self-defense or whether the right was only intended for state militias.

Because of the District of Columbia's status as a federal enclave (it is not in any U.S. state), the decision did not address the question of whether the Second Amendment's protections are incorporated by the Due Process Clause of the Fourteenth Amendment to the U.S. Constitution against the states. This point was addressed two years later by McDonald v. City of Chicago (2010), in which it was found that they are.

On June 26, 2008, the Supreme Court affirmed by a vote of 5 to 4 the U.S. Court of Appeals for the D.C. Circuit in Heller v. District of Columbia.478 F.3d 370 (D.C. Cir. 2007), cert. denied, 128 S. Ct. 2994 (2008)Misc. order Certiorari Denied p.2; Court: A constitutional right to a gun The Supreme Court struck down provisions of the Firearms Control Regulations Act of 1975 as unconstitutional, determined that handguns are "arms" for the purposes of the Second Amendment, found that the Regulations Act was an unconstitutional ban, and struck down the portion of the Act that requires all firearms including rifles and shotguns be kept "unloaded and disassembled or bound by a trigger lock". Prior to this decision, the law at issue also restricted residents from owning handguns except for those registered prior to 1975.

Lower court background In 2002, Robert A. Levy, a senior fellow at the Cato Institute, began vetting plaintiffs with Clark M. Neily III for a planned Second Amendment lawsuit that he would personally finance. Although he himself had never owned a gun, as a constitutional scholar, he had an academic interest in the subject and wanted to model his campaign after the legal strategies of Thurgood Marshall, who had successfully led the challenges that overturned school segregation. They aimed for a group that would be diverse in terms of gender, race, economic background, and age and selected six plaintiffs from their mid-20s to early 60s: three men and three women; four white and two black:

Tracey Ambeau (now Tracey Hanson) An employee of the U.S. Department of Agriculture. Originally from St. Gabriel, Louisiana, she lived in the Adams Morgan neighborhood of D.C. with her husband, Andrew Hanson, who was from Waterloo, Iowa. They lived in a high-crime neighborhood near Union Station in D.C. She grew up around guns and wanted one to defend her home. Dick Anthony Heller A licensed special police officer for the District of Columbia. For his job, Heller carried a gun in federal office buildings, but was not allowed to have one in his home. Heller had lived in southeast D.C. near the Kentucky Courts public housing complex since 1970 and had seen the neighborhood "transformed from a child-friendly welfare complex to a drug haven". Heller had also approached the National Rifle Association (NRA) about a lawsuit to overturn the D.C. gun ban, but the NRA declined. George Lyon A communications lawyer who had previously contacted the NRA about filing a lawsuit to challenge the gun laws in the District of Columbia. Lyon held D.C. licenses for a shotgun and a rifle, but wanted to have a handgun in his home. Tom G. Palmer A colleague of Robert A. Levy at the Cato Institute and the only plaintiff that Levy knew before the case began. Palmer, who is gay, defended himself with a 9mm handgun in 1982. While walking with a friend in San Jose, California, he was accosted by a gang of about 20 young men who used profane language regarding his sexual orientation and threatened his life. When he produced his gun, the men fled. Palmer believes that the handgun saved his life. Shelly Parker A software designer and former nurse who had been active in trying to rid her neighborhood of drugs. Parker was a single woman whose life had been threatened on numerous occasions by drug dealers who had sometimes tried to break into her house. Gillian St. Lawrence A mortgage broker who lived in the Georgetown section of D.C. and who owned several legally registered long guns that she used for recreation in nearby Chantilly, Virginia. It had taken St. Lawrence two years to complete the registration process. She wanted to be able to use these guns to defend herself in her home and to be able to register a handgun.

Previous federal case law pertaining to the question of an individual's right to bear arms included United States v. Emerson, 270 F.3d 203 (5th Cir. 2001), which supported the right and Silveira v. Lockyer, 312 F.3d 1052 (9th Cir. 2002), which opposed the right. The Supreme Court ruling in United States v. Miller, 307 U.S. 174 (1939) was interpreted to support both sides of the issue.

District Court In February 2003, the six residents of the District of Columbia filed a lawsuit in the District Court for the District of Columbia, challenging the constitutionality of provisions of the Firearms Control Regulations Act of 1975, a local law (part of the District of Columbia Code) enacted pursuant to District of Columbia home rule. This law restricted residents from owning handguns, excluding those grandfathered in by registration prior to 1975 and those possessed by active and retired law enforcement officers. The law also required that all firearms including rifles and shotguns be kept "unloaded and disassembled or bound by a trigger lock." They filed for an injunction pursuant to , 2202, and . District Court Judge Emmet G. Sullivan dismissed the lawsuit on March 31, 2004.

Court of Appeals On appeal, the U.S. Court of Appeals for the D.C. Circuit reversed the dismissal in a 2-1 decision. The Court of Appeals struck down provisions of the Firearms Control Regulations Act as unconstitutional. Judges Karen L. Henderson, Thomas B. Griffith and Laurence H. Silberman formed the Court of Appeals panel, with Senior Circuit Judge Silberman writing the court's opinion and Circuit Judge Henderson dissenting.

The court's opinion first addressed whether appellants have standing to sue for declaratory and injunctive relief in section II (slip opinion, at 5–12). The court concluded that of the six plaintiffs, only Heller – who applied for a handgun permit but was denied – had standing.

The court then held that the Second Amendment "protects an individual right to keep and bear arms", that the "right existed prior to the formation of the new government under the Constitution", also stating that the right was "premised on the private use of arms for activities such as hunting and self-defense, the latter being understood as resistance to either private lawlessness or the depredations of a tyrannical government (or a threat from abroad)." They also noted that though the right to bear arms also helped preserve the citizen militia, "the activities [the Amendment] protects are not limited to militia service, nor is an individual's enjoyment of the right contingent upon his or her continued or intermittent enrollment in the militia." The court determined that handguns are "Arms" and concluded that thus they may not be banned by the District of Columbia.

The court also struck down the portion of the law that requires all firearms including rifles and shotguns be kept "unloaded and disassembled or bound by a trigger lock." The District argued that there is an implicit self-defense exception to these provisions, but the D.C. Circuit rejected this view, saying that the requirement amounted to a complete ban on functional firearms and prohibition on use for self-defense:Parker Opinion, Opinion of the Court, p. 57. "He simply contends that he is entitled to the possession of a 'functional' firearm to be employed in case of a threat to life or limb. The District responds that, notwithstanding the broad language of the Code, a judge would likely give the statute a narrowing construction when confronted with a self-defense justification. That might be so, but judicial lenity cannot make up for the unreasonable restriction of a constitutional right. Section 7-2507.02, like the bar on carrying a pistol within the home, amounts to a complete prohibition on the lawful use of handguns for self-defense. As such, we hold it unconstitutional."

In her dissent, Circuit Judge Henderson stated that Second Amendment rights did not extend to residents of District of Columbia, writing:

In April 2007, the District and Mayor Adrian Fenty petitioned for rehearing en banc, arguing that the ruling created inter- and intra-jurisdictional conflict. On May 8, the Court of Appeals for the D.C. Circuit denied the request to rehear the case, by a 6–4 vote.

Supreme Court The defendants petitioned the United States Supreme Court to hear the case. The Supreme Court granted certiorari on November 20, 2007.Cert. granted, District of Columbia v. Heller 128 S. Ct. 645 (2007). The court rephrased the question to be decided as follows:

This represented the first time since the 1939 case United States v. Miller that the Supreme Court had directly addressed the scope of the Second Amendment.

Amicus curiae briefs Because of the controversial nature of the case, it garnered much attention from many groups on both sides of the gun rights issue. Many of those groups filed amicus curiae (friend of the court) briefs, about 47 urging the court to affirm the case and about 20 to remand it.

A majority of the members of Congress signed the brief authored by Stephen Halbrook advising that the case be affirmed overturning the ban on handguns not otherwise restricted by Congress. Vice President Dick Cheney joined in this brief, acting in his role as President of the United States Senate, and breaking with the George W. Bush administration's official position. Arizona Senator John McCain, Republican, also signed the brief. Then-Illinois Senator Barack Obama did not.

A majority of the states signed the brief of Texas Attorney General Greg Abbott, authored by Abbott's solicitor general, Ted Cruz, advising that the case be affirmed, while at the same time emphasizing that the states have a strong interest in maintaining each of the states' laws prohibiting and regulating firearms. Law enforcement organizations, including the Fraternal Order of Police and the Southern States Police Benevolent Association, also filed a brief urging that the case be affirmed.

A number of organizations signed friend of the court briefs advising that the case be remanded, including the United States Department of Justice and Attorneys General of New York, Hawaii, Maryland, Massachusetts, New Jersey, and Puerto Rico. Additionally, friend of the court briefs to remand were filed by a spectrum of religious and anti-violence groups, a number of cities and mayors, and many police chiefs and law enforcement organizations.

A collection of organizations and prominent scholars, represented by attorney Jeffrey Teichert, submitted an "errors brief" arguing that many of the common historical and factual "myths and misrepresentations" generally offered in favor of banning handguns were in error. Teichert's brief argued from a historical perspective that the Second Amendment protected an individual right to keep and bear arms.

Oral arguments