Let's take both sides' best point. It isn't just guns, and it isn't just crazy people. The Sandy Hook problem is crazy people using guns. I see it as a two-part chemical weapon: separately innocuous, but having a very narrow but extremely dangerous mixing of the two.
I like the solution that a tax on weapons & ammo pays for better mental health programs. This moves the two parts farther apart from each other.
Not the folly of disarming lawful people, or the fantasy of disarming everyone, and not a fantasy of de-crazying the world, or putting a cop in every school. Just a small, real movement of the two apart from each other.
I'm for universal mental-criminal checks, but I know that only solves a teensy (but "easy") bit of the problem: at best it would have delayed the Virginia Tech shooter. That guy had a short, crazy, angry, lifetime--however long it lasted--to cook up a mass killing. But delaying mass killings is a good thing (it should net-reduce their numbers too).
The Sandy Hook shooter stole his mother's guns. Background checks offer *zero* there: His mom was a nice, law-abiding teacher-lady--the kind of person we should be happy to see have a gun for her own protection, and who is the last person any feasible law would ever see disarming.
Problem is, with widespread legal gun-ownership, nut-cases have plenty of perfectly-nice people whom they can steal guns from, and unlimited time to find the key to the gun-cabinet.
Gun-freedom people have a good point that personal ownership of guns can be correlated with reduced property/petty crimes, and that peaceful society can be compatible with gun-ownership (as in Switzerland).
Gun-control people have a good point when they note that nut-cases are *empowered* in a unique way by guns, and in a uniquely-powerful way by powerful guns--something we don't see with other powerful/dangerous things like cars, gasoline, or knives.
Ergo, let the gun owners keep all their keep-and-bear freedoms, but limit the dealing. Gun show background checks would have been a freakish imposition in 1994 (The Brady Bill was pre-internet and practically pre-cellphone), but in 2013, *not* asking gun-shows to supply wifi and all dealers to have an instant check-app seems a freakish oversight.
And tax. We all have a need/incentive to help the mentally ill, but given the explosive mix of guns and crazy, gun owners/users/dealers/makers need to take a little more of it.