What would happen if every American citizen was required to own a gun and know how to use it? They have tried restrictions that clearly don’t work.
The campus was a “gun free zone.” A few students or faculty with concealed carry would have been able to stop the shooter before he killed so many. A “gun free zone” means that there will not be anyone to stop killers like Harper-Mercer.
The best way to stop bad guy with a gun is a good guy with a gun.