Exactly what laws would have prevented this shooting?

1. The reason that there were only about 10 deaths was because he didn't use an "assault rifle". If he had, there would have been closer to 30-40 deaths. So the laws that kept him from getting an assault rifle saved most of the lives that would have been lost if he had one.

3. He didn't own the gun, but someone did. Laws keeping that person from owning a gun would have kept him from getting it, and would have prevented the shooting.

Laws against murder don't prevent all murders, but that doesn't mean we shouldn't have the law. Duh.

The parents are at fault for having guns accessible in the home to this shooter. They were breaking the law.

In many developed countries, gun control laws include locked storage of guns and ammo separately, which make it much more difficult for someone not authorized to have the guns, get the guns.

If enough teachers were allowed to be trained and have a concealed carry weapon, shooters would think twice about entering a school and shooting people. The vast majority of mass shooters do their shooting in a place where it's unlikely that anyone will shoot back at them.

The Aurora theater shooter bypassed two other theaters with midnight screenings of Batman and chose to go to the theater that had a policy banning firearms to do his shooting. The San Antonio theater shooter didn't plan ahead as well and rather than being a mass-shooter, he ended up being a single-injury shooter before getting himself killed by someone shooting back at him.

ps: burglars like the idea of requiring people to keep their guns locked up in a safe.

Metal detectors. Let's bring our troops home from Korea and Germany and put them to work guarding our schools.

Americans are just getting a hint as to how it feels to live in a war zone.

A pistol and shotgun that belonged to his father.

Maybe legislation that would hold firearm owners liable for not properly taking care of and securing their firearms, or if they gave them willing to a 17 year old.

Zero

Perhaps if we made it a felony for adults to leave firearms unsecured around children it might actually have an impact.

A law that his father should have a secure, locked gun cabinet that was in no way accessable to this killer.