Mandatory in the same way that math or science or english or history is mandatory? Yes. Mandatory in order to buy a gun? No.
I think the goal should be to increase firearm safety and general awareness of firearms, not to create a bureaucracy to manage gun training licenses.
It won't ever happen. Given the political climate, the last thing the liberals want is students being taught about guns in school. Kids are getting suspended for blowing bubbles at each other with hello kitty bubble guns.
Imagine a pathologically idealistic, anti-religious, culturally-relativistic, iconoclastic, socially-irreverent, sociologically-progressive signature line here. Or don't.