Succeeding generations of federal judges have winnowed away at the ability of Americans to exercise that right, but it exists nonetheless, and for a very good reason.
The American Revolution, the first in history where armed citizens rebelled against the abuses of the rights of man perpetuated by a colonizing power, could not have succeeded were it not for the private ownership of firearms.
As Hamilton writes in Federalist 28, "If the representatives of the people betray their constituents, there is then no resource left but in the extension of the original right of self-defense which is paramount to all positive forms of government, and which against the usurpations of the national rulers may be exerted... The citizens must rush tumultuously to arms, without concert, without system, without resource; except in their courage and despair."
The amendment's reference to "a well-regulated militia" is the founder's annoiting of who, in times of difficulty or invasion, should be in command of efforts to repel invaders or to suppress a rebellion against the constitutional system like the 1794 Whiskey Rebellion, the first test of the new central government.
Even within that kind of structure, the founders expected the arms employed would generally if not exclusively be the property of the men and boys wielding them in the name of liberty.
The Ashcroft letter, which reinforces the private ownership of arms, is not a new policy. It rescinds a position taken by the Clinton administration that contravened the traditional interpretation, several centuries old. What the attorney general has done it to restore the view that was held before Janet Reno and her cronies took hold of the department of justice.
Liberty is not easy nor does it come cheaply. It is a given that hunting and sport are legitimate uses private firearms. Yet that no more what the second amendment is about anymore than it is what the Constitution is about.
The Constitution and the Bill of Rights, the world's first written effort to organize a national government while placing explicit limits on that government's powers, are about human freedom and about reserving to the people the right and ability to protect that freedom from enemies, "both foreign and domestic." They are, like firearms, tools to safeguard our liberties.