The Second Amendment states, '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.' For two centuries, courts read this as protecting state militias (the National Guard), not individual gun ownership. That changed in 2008 when the Supreme Court ruled 5-4 in District of Columbia v. Heller that individuals have a constitutional right to own guns for self-defense in the home. Justice Antonin Scalia wrote that the right isn't unlimited: governments can ban felons from owning guns, prohibit weapons in schools, and regulate gun sales. Two years later, McDonald v. Chicago applied this right to states through the 14th Amendment. Post-Heller courts have upheld background checks, assault weapon bans (in some circuits), and concealed carry permit requirements, though in 2022 the Court struck down New York's century-old law requiring applicants to prove 'proper cause' for a carry permit. The amendment's opening militia clause and its individual-rights guarantee have remained in tension in every major gun case since Heller, driving ongoing disputes over which regulations survive constitutional challenge.