Just some of my thoughts on the subject. Let me state that I don't have the answers. Just my opinions.
First off; our lawmakers, with the support of the general public, have created Killing Fields in our schools and anywhere else that is determined to be a Gun Free Zone. This is, in itself, an infringement on the 2nd. Amendment. If our Legal System wasn't so much a part of the problem, this could be corrected. A few class action law suits againt these lawmakers might open some eyes.
Secondly; The number of Presidents, Vise-Presidents and Politicians that are protected by the Secret Service is a very small number compared to the number of schools that are spread across our nation.
Thirdly; How would you provide the Security??
1. Armed Guards? Possibly more than one per school. If a Perp. was determined to take out a school and they took out that single guard first, the door is open. How many would it take to provide adequate back-up? The guard would, most likely be in uniform and open carry. Thus making them easy to identify and take out.
2. Select from volunteers that are already on the school payroll. Principles, Teachers, Custodians, Bus Drivers, etc. Give them proper training and sufficient armament even if it required a slightly higher pay scale. These employees would carry concealed and/or have ready access to a secure vault.
3.Maybe hire additional staff with limited duties that allow for free range of the school but who's primary duty is security. These staff members would be trained and carry concealed. Making them less obvious and less of a target.
4. Hire senior citizens at a reduced pay grade that are retired and committed to protecting our kids. Training would be required. The most obvious choice would be retired military or retired LEOs but wouldn't be limited to that group. I know a retired LEO that works part time at Walmart that would be an excellent candidate for the job.
5. Home school.
At any rate, while the public is pointing fingers, the politician and lawmakers should be first on the list for creating these Killing Fields in the first place.
I would be interested in other's thoughts.