Another Sandy Hook cannot be prevented by the State

It must be We the People who protect ourselves, our children, and the children of our neighbors, just as the state's giant security apparatus failed to stop the shoe bomber or the underwear bomber, and citizens succeeded.  If we are to prevent tragedies like Sandy Hook, we must be willing to act as these brave civilians did, and we must be empowered to do so.

With this in mind, I suggest a we implement a federal level Unrestricted Concealed Carry law - all handgun owners may carry concealed at any time in any public place, except police stations, courts, and jails.  This law will ban "Gun Free Zones" at all other public properties - again, excepting police stations, courts, and jails.  It will be enforced via the 2nd and 14th Amendments and the supremacy clause, and thus would preempt any and all state law with regards to the carrying of firearms.

Furthermore, this law should state explicitly that private property owners have the right to designate their property as "gun free zones," and that if they do so they are fully responsible for the protection of their visitors and patrons and are fully liable for any injury sustained during an act of violence - with no exceptions.

I'm also interested in some kind of regularly provided shooting practice for handgun owners, but not quite sure how to implement it.  Perhaps the National Guards can be reverted to state militias and all citizens can train through them.

Update:
Such an excellent letter dug up by the Smallest Minority:

Freedom takes practice...

It's not just that rights are useless if they are not exercised, not even that rights must be used or be lost. It's that exercising your rights, constantly, is what instructs you in how to be worthy of them.

Being armed goes far beyond simple self-protection against thugs or even tyrants - it's an unequivocal and unmatched lesson that you are politically and morally sovereign; that you, and not the state, are responsible for your life and your fate. This absolute personal sovereignty is the founding stone of the Republic.

"A well-regulated militia" (where the militia is "the whole people") isn't just "necessary to the security of a free state" because it provides a backup to (and defense against) the police and the army. More importantly, keeping and bearing arms trains sovereign citizens in the art of freedom, and accustoms us to our authority and duty.