It's not like he bought them on the black market or anything, "All three weapons that Lanza had with him were bought legally and were registered to Lanza's mother." But, really, that's not the point that I was trying to make. The point is that in most mass/spree shootings, the guns used were purchased legally. That is a problem. Gun control laws are not about taking your hunting rifle or personal protection gun away, they are about preventing guns from getting into the hands of people who shouldn't have them.
Well, the problem is how do you decide?
Many people fit some sort of profile, but will never do that. Many people who might do it avoid health services where it is available. Some of the states with stricter gun laws are strict because of prior problems, but they have been strict for decades. How long do you look before you say they're a failure?
Regulating the guns themselves is complicated. Millions of magazines already exist. Millions of semi automatic guns already exist (including millions of shotguns and rifles used for hunting.) The last assault weapon ban basically targeted scary LOOKING guns. To come up with something that will actually work is much harder.
Before we spend any money on restricting guns, I'd rather the money be spent on metal health, but even that will be very hard to use to specifically look for mass killers.
(PS, last year an average of 27 people died per day due to drunk driving. Mass murders are statistically very rare and an unlikely way to die compared to more mundane things that kill many more people. Last year nearly 3x more people were killed by cars. That is still a ton of unacceptable deaths by people with guns but it does help to keep some perspective.)
