The Second Amendment to the United States Constitution provides for the right to keep and bear arms, and 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."

Some people believe this language creates a Constitutional, individual right for citizens of the United States to keep and bear arms, and prohibits Congress and state legislatures from prohibiting or restricting the possession of firearms.

Others believe the beginning words ("A well regulated militia being necessary”) indicate the intent of the Amendment was only to restrict Congress from limiting a state’s right to self-defense. This collective rights theory of the Second Amendment holds that citizens do not have an individual right to possess firearms, and that federal, state, and local legislative bodies may regulate the possession of firearms without implicating a Constitutional right.

At the time the First Amendment was ratified, some militia members used their own weapons, and some used weapons from their state’s militia stores.

In California, the Second Amendment to the United States Constitution is recognized, but the state has implemented comprehensive regulations regarding firearms that reflect a balance between individual rights to bear arms and public safety concerns. The state's laws are among the strictest in the nation, including background checks for all firearm purchases, an assault weapons ban, a 10-day waiting period, and restrictions on high-capacity magazines. California also has a 'red flag' law that allows law enforcement and family members to petition for a court order to temporarily remove firearms from someone who poses a danger to themselves or others. The interpretation of the Second Amendment has been subject to debate, with the individual rights perspective being supported by the Supreme Court's decision in District of Columbia v. Heller (2008), which held that the Amendment protects an individual's right to possess a firearm unconnected with service in a militia. However, the Court also recognized that the right is not unlimited and that firearms and their ownership can be regulated.