Please see the Legal Basis of the National Guard by going to their website:
http://www.arng.army.mil/aboutus/history/Pages/ConstitutionalCharterofth....
The original purpose of the 2nd amendment according to the Framers of our country was intended for the States the ability to establish a National Guard. It's intention wasn't for every individual the right to own firearms. If a person wants to own a gun, they should have to be actively serving in the US military, Secret Service, or local, state, or federal police force. If they are not, they should not be able to own a gun.