in order to form a more perfect union,
establish justice,
insure domestic tranquility
promote the general welfare
Obviously this is an issue of contention.
There are those among us who predicate the existence of Western Civilization on the ability to have an automatic rifle or perhaps a grenade launcher to keep the neighbors quiet.
While I am certain Thoreau probably had a cabinet full of rifles and pistols in the cabin on Walden Pond, that doesn't mean folks living off the Mass. Pike need AR-15's,M-16's and Kalishnakovs for protection and deer hunting in the Berkshires.
Free men are not afraid of their neighbors, unless they are the prisoner of their own fears.