The NRA is guilty of nothing more than stupidity.
Armed civilian volunteers in every school? Yeah, that's dumb. Real dumb. I put such stupidity on par with the desire to ban assault rifles... an absurd overreaction based on emotional appeals.
In my opinion, Canada and the United States ought to adopt the Switzerland model. I have no problem with an armed citizenry... but outside the framework of a militia, such freedom actually results in the encroachment of personal liberty, as it guarantees the militarization of police and the existence of a standing army.