http://reason.com/archives/2012/12/22/gun-restrictions-have-always-bred-defianEven if there were no guns in a country except in the hands of non- criminal/evil/tyrannical/civil rights-violating law enforcement officers (impossible), then murders using all other weapons (including fists and feet) increase. There will always be criminal violence where there is no ultimate equalizer. Law enforcement cannot protect each individual at all times.
The amount of violent deaths of any type in developed countries where no firearms are easily at hand for a large amount of the population are ridiculous compared to those of the US.
Obviously crime exists in similar ratios, but its just less violent, there are less violent deaths per habitant. Thieves, burglars, and other "property criminals" (which are 99% of the criminals) are rarely armed (if at all), which makes a huge a difference. We also have plenty of people that goes nuts for no apparent reason, but its just they do not even know how to use or where to find a gun, and any other weapon is simply uneffective and definitely not as cool as an "assault rifle" when planning to cause as much death as possible.
The statement that school would be safer if teachers carried guns is complete madness, that is the kind of world you want your kids to grow up? The example of Israel speaks pretty much for itself, that's a fucking war zone, is to Israel to what you compare your country to?
You don't have to be a genius to realize that if you have firearms at hand, and they form part of your life, its more likely for you to use one of them at some point... While the thought wouldn't even cross your mind if you never would have seen one closely in your life. And no, a knife is something completely different, you use knifes every day in your kitchen, they have plenty of uses, while a handgun only use is to kill someone. The approach when dealing with both "tools" is completely different, in both a practical and philosophical way.
Banning is never an answer, violence is something that is rotten in culture and that needs to be eradicated by the society as a whole, but for sure the gun-loving fucktards that defend that more guns = less deaths are not helping at all.