The schools in my system have a partnership with the police agencies and all secondary (middle and high) schools have School Resource Officers. They are positioned at the school all the time. They patrol the school and school events, do D.A.R.E. presentations, counsel students, and the like. They are also available to assist elementary schools if need be, although they are not stationed there. I'm not for armed citizens in schools with firearms, not even some people I know.
I recently adopted two rescue cats from the ASPCA and it was a long, complicated, and expensive process. I could walk into WalMart or KMart today during my lunch break today and purchase a gun in less time and for less money than my two cats cost me. Something's not right with that picture. Consider everything you have to do to get a Driver's License compared to what you have to do to purchase a gun.
The hole in the "don't take guns from law abiding citizens" argument is that, in all the last dozen mass murders, each one of those accused was a "law abiding citizen" right up until they killed people. Which brings us to the point where we as a nation have to come together, not make this come liberal-conservative or urban/rural battle and really talk about a proper screening process for individuals who want to purchase firearms and whether certain types of firearms should even be sold to citizens. The standard of "law abiding citizen" doesn't appear to be stringent enough.
Complication makes it easy to explain failure.