If you trained and armed all students and faculty with ar-15s and gave advanced classes on tactics to take down shooters, shooters would be unlikely to take on an highly armed and trained force of students and faculty.
I don't think that would be an effective deterrent.
At the beginning of the last century, there was a man named Hiram Maxim. He invented the machine gun, which he happily sold to the major powers in Europe, the US and Britain. At this time tensions in Europe were escalating and war was looking and more likely.
You know why he sold them to both the Entendre and the Axis powers?
Besides making him a shit tonne of money?
He believed that if all sides had an abundance of these devastating death machines, they couldn't be foolish enough to fight wars with each other. That no one could send countless thousands of men charging to their certain slaughter.
He was wrong. The first world war began in 1914. Throughout the entirety of the war, sending men over the top in mass infantry charges into the machine guns to their certain slaughter was the go to tactic for infantry commanders. This was repeated over and over.
Apparently they really were that foolish.
Hiram Maxim actually thought his machine gun would save lives. Instead more than a million men of both sides were cut down by this "peace" machine.
Also, if you banned all firearms, knifes, chemicals that could be used to create bombs, etc it would be extremely difficult to find something to hurt multiple people with
This could work, but we'd all have to give up a few creature comforts.
Without knives, we'd have to butter our toast with our fingers. Making a steak and eating it would become a real pain in the ass. Imagine trying to butcher a cow with a tablespoon.
Chemicals that can be used to make a bomb are a little more difficult to go without.
- We'll have to switch back to horses and bicycles, as gasoline, diesel, propane, butane, uranium, hydrogen to name a few. All banned. No more fuel for cars. No more forced air heating or stable electricity. Massive spike in air pollution after coal and wood become the primary fuels again. Possibly resumption of the use of whale oil if we get desperate.
- You'll have to clean your toilet with your bare hands. Cleaning chemicals and varsol would be banned. Elbow grease only.
- Industrial fertiliser, banned.
- Compressed gas cylinders of any kind, banned.
- Radiomedicine. Exploratory surgery for diagnosing internal health problems an x-ray can't see would become frequent again. As would deaths from complications of surgery would spike, survivial rates of cancer would drop significantly. Caesium, banned.
I don't know if I could live without some of those.
Even with all that gone, there's nothing stopping someone from beating me to death with a stick.