Here is my take on gun control.
I don't think gun laws would have changed the fact of the VT shootings. The nature of the massacre might have been different. The Shooter might have had to get his guns somewhere else. he might have had to use 4 guns to prevent frequent reloading. Maybe fewer than 32 people would have died but there would have been a shooting. 32? 10? It matters to the victims and their families but does it matter from a policy perspective?
The impact of fewer guns in America, I believe, would be on the domestic front. How many shootings run like this. Dean gets into an argument with Jerry. It gets heated. Dean has a gun in his house. Dean thinks, I am going to shoot that SOB. Dean goes to his home, retrieves his pistol, returns to the location where he confronted Jerry and kills him. Now we can't outlaw anger or confrontation but reducing the likelihood that a firearm is available would reduce at least one kind of common homicide.
I know Dean could return with a baseball bat or a knife but Jerry has a fighting chance against an attacker at close range and his injuries are less likely to be life-threatening.