The cities with the strictest gun-control laws often have the highest crime rate per capita. Thus, if weapons are kept in the hands of dangerous criminals, and not law-abiding citizens as well, who is the Second Amendment really protecting?
In MED Countries where guns are illegal (without full license, and then are only ever usually hunting guns), gun crime is exceedingly low. It does happen, but it happens everywhere.
In the UK, compared to population, guncrime is considerably lower than the USA.
However, I believe knife-crime is higher in the UK than the USA.
But at the very least, it's easier to defend myself from a knife than it is to defend from a gun. Particularly at range.
Eliminating guns would make the gun violence worse. If you were a criminal, and you weren't sure if your burglee had a gun, would you try to rob their house? Or if you're in a school, and you don't know if all of the teachers have firearms, would you shoot it up? No, of course not.
This is obviously not true. There are plenty of criminals who break into houses regardless of the fear of the occupants owning guns.
And just because someone owns a gun it does not mean at all that they constantly have them at arms length because they are constantly anticipating an attack. There seems to be some unusual level of paranoia in pro-gun supporters in assuming everyone wishes to attack them.
And I'm pretty sure most school teachers do not bring a gun into school. They might own them in their own time, but why would you bring it in to school where you work? How many parents would just see that as purely dangerous, in that it would be so easy for the teacher himself to lose it and shoot someone, or for the gun to get stolen or used by a student? How much stuff would they be in if that ever broke out to the public?
And sorry to be blunt and possibly disrespectful, but if this is the case, then how come all these school gun-shootings don't end sooner when a teacher shoots the attacker?