I dunno how to work it in, but anything referring to a "body of people" opens the door to those who want to sell the collective rights idea. The first point to make is the right is individual, not collective, and that the militia is formed from individuals.
I think I would reverse the language, along something like this:
"The right of an individual to keep and bear arms shall not be infringed. This individual right is to secure the self-defense of liberty, person and property, or, by an assembly of individuals the defense of this free state or subdivisions thereof, against threats small or large, local or foreign."
Loyalty to petrified opinions never yet broke a chain or freed a human soul in this world — and never will.
— Mark Twain