The Second Amendment to the United States Constitution, ratified on December 15, 1791, as part of the Bill of Rights, protects the right of the people to keep and bear arms. Its exact wording is: "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."

The Amendment was originally intended to ensure the effectiveness of state militias as a check against a standing federal army and to secure the security of a free state. Over time, it has been interpreted to protect an individual's right to possess firearms for lawful purposes such as self-defense, including defense of the home.

Key points about the Second Amendment include:

• It establishes a constitutional right for individuals to keep and bear arms.

• The prefatory phrase about a "well regulated Militia" reflects historical context about militias' role in national defense and limiting federal military power.

• The Supreme Court has affirmed the individual right interpretation in cases such as District of Columbia v. Heller (2008) and McDonald v. City of Chicago (2010), while also recognizing certain limits on this right, such as prohibitions on possession by felons or the mentally ill.

• The Amendment was influenced by English common law and the English Bill of Rights of 1689, emphasizing self-defense and resistance to oppression.

In summary, the Second Amendment guarantees Americans the right to keep and bear arms, primarily for self-defense and as a safeguard of liberty, while allowing for reasonable government regulations.