The right to keep and bear arms in the United States is a fundamental right protected by the Second Amendment to the United States Constitution, part of the Bill of Rights, and by the constitutions of most U.S. states. The Second Amendment declares:
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.
In the United States, which has an English common law tradition, the concept of a right to keep and bear arms was recognized prior to the creation of a written national constitution. When colonists in the Thirteen Colonies rebelled against British control during the American Revolution they cited the 1689 English Bill of Rights as an example.
English precedent.
The American understanding of the right to keep and bear arms was influenced by the 1689 English Bill of Rights, an Act of Parliament, which also dealt with personal defense by Protestant English subjects.
The Bill of Rights did not create a new right to have arms but rather rescinded and deplored acts of the deposed King James II, a Roman Catholic, who had forced the disarming of Protestants, while arming and deploying armed Catholics contrary to Law (among other alleged violations of individual rights). The Bill of Rights provided that Protestants could bear arms for their defense as permitted by law. It also established that the power to regulate the right to bear arms belonged to Parliament, not the monarch.
Sir William Blackstone wrote in the eighteenth century about the right to have arms being auxiliary to the "natural right of resistance and self-preservation", but conceded that the right was subject to their suitability and allowance by law.
The fifth and last auxiliary right of the subject, that I shall at present mention, is that of having arms for their defence, suitable to their condition and degree, and such as are allowed by law. Which is also declared by the same statute and is indeed a public allowance, under due restrictions, of the natural right of resistance and self-preservation, when the sanctions of society and laws are found insufficient to restrain the violence of oppression.