Extracts from Wikipedia
A foundation of American political thought during the Revolutionary period was the well justified concern about political corruption and governmental tyranny. Even the federalists, fending off their opponents who accused them of creating an oppressive regime, were careful to acknowledge the risks of tyranny. Against that backdrop, the framers saw the personal right to bear arms as a potential check against tyranny. Theodore Sedgwick of Massachusetts expressed this sentiment by declaring that it is "a chimerical idea to suppose that a country like this could ever be enslaved . . . Is it possible . . . that an army could be raised for the purpose of enslaving themselves or their brethren? or, if raised whether they could subdue a nation of freemen, who know how to prize liberty and who have arms in their hands?" Noah Webster similarly argued:
Before a standing army can rule the people must be disarmed; as they are in almost every kingdom in Europe. The supreme power in America cannot enforce unjust laws by the sword; because the whole body of the people are armed, and constitute a force superior to any band of regular troops that can be, on any pretence, raised in the United States.
George Mason argued the importance of the militia and right to bear arms by reminding his compatriots of England's efforts "to disarm the people; that it was the best and most effectual way to enslave them . . . by totally disusing and neglecting the militia." He also clarified that under prevailing practice the militia included all people, rich and poor. "Who are the militia? They consist now of the whole people, except a few public officers." Because all were members of the militia, all enjoyed the right to individually bear arms to serve therein.
The framers thought the personal right to bear arms to be a paramount right by which other rights could be protected. Therefore, writing after the ratification of the Constitution, but before the election of the first Congress, James Monroe included "the right to keep and bear arms" in a list of basic "human rights", which he proposed to be added to the Constitution.
Patrick Henry, in the Virginia ratification convention June 5, 1788, argued for the dual rights to arms and resistance to oppression:
Guard with jealous attention the public liberty. Suspect everyone who approaches that jewel. Unfortunately, nothing will preserve it but downright force. Whenever you give up that force, you are inevitably ruined.
While both Monroe and Adams supported ratification of the Constitution, its most influential framer was James Madison. In Federalist No. 46, he confidently contrasted the federal government of the United States to the European kingdoms, which he contemptuously described as "afraid to trust the people with arms." He assured his fellow citizens that they need never fear their government because of "the advantage of being armed...."
By January of 1788, Delaware, Pennsylvania, New Jersey, Georgia and Connecticut ratified the Constitution without insisting upon amendments. Several specific amendments were proposed, but were not adopted at the time the Constitution was ratified. For example, the Pennsylvania convention debated fifteen amendments, one of which concerned the right of the people to be armed, another with the militia. The Massachusetts convention also ratified the Constitution with an attached list of proposed amendments. In the end, the ratification convention was so evenly divided between those for and against the Constitution that the federalists agreed to amendments to assure ratification. Samuel Adams proposed that the Constitution:
Be never construed to authorize Congress to infringe the just liberty of the press, or the rights of conscience; or to prevent the people of the United States, who are peaceable citizens, from keeping their own arms.