If we look at statistics, I think it's important to notice that America has had more school shootings than most every western European country combined. We should also then notice that all of those countries that have had abysmally low shootings, comparatively, have also either completely banned, or practically banned, civilian fire-arm usage.
I understand the sentiment in protecting children completely, but the American approach is obviously not working as is. And to say that banning guns is not the solution because then the children are left defenseless is overlooking history. Sandy Hook's shooter had a legally registered firearm (that he stole from his mother), and Columbine had guns on the school's side as well, yet both of these cases resulted in excessive loss of life regardless.
I know that in most cases, banning things only leads to unregulated black-market/cartel trade, but we have to realize that the majority of the wack-jobs who go on to use these guns to commit acts of violence against innocents simply do not have the mental capacity or resources of acquiring illegal ammunition, only illegal organizations that have no reason to shoot up anyone but rivals, which is unavoidable and mute to this argument.
Fighting fire with fire only leads to more fire. But that's just my opinion.