"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."
When the Second Amendment was adopted, states formed and raised militias from male volunteers who provided their own muskets. Nowadays, national defense is conducted quite differently. We have a standing army and defense is by far the largest piece of the federal budget. Volunteers who enlist in the armed forces are seldom called upon now to provide their own SAM's, machine guns, grenades, or tanks.
Most of the arguments for upholding the 2nd Amendment heard these days run along the lines of we need firearms for personal protection or hunting or some such. Security of the state does not seem to be an argument we hear much of. Does the fact that the framers of the Constitution explicitly stated that state security was the reason that arms would be permitted to the people add credence to the notion that this Constitutional provision may be obsolete?