They knew that we would need to change The Constitution that is why there are 2 ways to amend The Constitution. The Second Amendment was about the ownership of military weapons. So, we could be proficient with their use when called up to war, for self-defense, for food and for protecting from a tyrannical govt.
In 1785 Thomas Jefferson wrote to his fifteen-year-old nephew, Peter Carr, regarding what he considered the best form of exercise: "...I advise the gun. While this gives a moderate exercise to the body, it gives boldness, enterprize, and independance to the mind. Games played with the ball and others of that nature, are too violent for the body and stamp no character on the mind. Let your gun therefore be the constant companion of your walks."
https://www.monticello.org/site/research-and-collections/firearms
What part of the people's right to keep and bear arms SHALL NOT BE INFRINGED don't you understand? Arm the dang teachers /staff. All the mass murders have only one thing in common GUN FREE ZONES so ban the zones
RE: Massachusetts District Court Judge William Young rules that AR-15s and large capacity magazines are not protected by Second Amendment