No one with half a brain is gonna argue that mentally unstable citizens should be able to own assault weapons. In my state the process for owning a gun is quite thorough. Getting a pistol and CC permit is beyond difficult. It's a states issue and should be, but there are some ground rules that should be set.
We dont disagree but there are a lot of people arguing control to the point that they should have access to all type of crazy firearms. They may not have half a brain, but they are political power houses. Also no one knows who is mentally unstable, and no one can predict when someone is who seems sane is going to crack. If you could then seemingly sane people in areas where "this never happens" would be able to be controlled. You cant control that...thats an illusion, and while people try to control it innocent people will die from bullets fired by social parasites.