There are a couple of problems with using armed civilian volunteers to support law enforcement in protecting schools. 

One is that roughly half of those children will be from families who vote Democrat habitually, and THOSE people HATE civilians having firearms. So they will probably litigate to prevent such a thing from happening. 

Another is the moral issue of a bunch of vicious cowards like many 'Crats, expecting self-armed citizens (and legal residents?) to protect their children and put their own lives at risk, when the 'Crats will be the first to crucify (criminally/civilly) any such armed civilian who makes an honest mistake and does the wrong thing. 

So expecting people who exercise their 2A entitlement to protect the children of people who obviously despise them, is a problem too. On the one hand 'Crats will eagerly accept the help of armed civilians putting their own lives at risk to protect children of 'Crats, while their political party is doing everything possible to persecute, prosecute, oppress and subjugate those very same people for having firearms at all. 

Vicious (anti-2A fanatic) cowards have no place in our culture. They are cacogens unworthy of regard, accommodation or (least of all) authority. Parasites. 

The population of Israel seems to have more mature/serious-minded/edumacated(sic) people than the U.S. So a program which draws armed support from Israeli civilians may work fine. 

Is the U.S. population actually more sue-happy than Israel's? I wonder.