Paddock's only prior was a traffic violation. No red flag there.
Sound Mental Health:
Really? Should I not be able to buy a gun because I spent 6 years talking to a variety of MSW's and PhD's about my mother? Do we really want to create a disincentive to the seeking of care for mental illness by suggesting that obtaining a diagnosis will culminate in forfeiture of rights?
I've heard some other bizarre proposals including liability insurance, sin taxes.
But here is the cold hard fact. Paddock was a rich, white man who had led an officially blameless life. Between wealth and white privilege, were guns completely illegal in the US, he would have had the means to obtain them, transport them, and would have likely remained undeterred.
So that's why this event should be regarded as essentially useless to the gun debate.
Phase 2: National Unity.
We need to think reasonably about guns, and we need to place the conversation in context. Guns are lethal force, and their use is highly context sensitive.
City dwellers see guns most commonly in association with crime. This is because really there's not much one can do with a gun in city life except use it to kill another person or leverage the threat of killing another person to effect a property crime. Gun hobbyists, former military folk, and law enforcement might take guns to shooting ranges, and skeet (clay) shooting is enjoying some popularity as a sport. Urban gun owners might go into the woods every fall to hunt deer, and stock their freezer with some meat they can boast about having gotten on their own. But the fact is no one in a city really NEEDS a gun. The most frequent reason cited for handgun ownership is "self defense," which tends to be a code for wanting level footing with a hypothetical armed assailant. This being said, gun ownership in cities should be viewed as a luxury. A luxury tax on guns and ammo should not prove an undue burden on people who are essentially buying guns in pursuit of enjoyment.
Rural dwellers are another matter entirely. Here the lethal force factor is far less likely to be getting leveraged against people, and target shooting is the honing of an important life skill, rather than a hobby. Lethal force is likely to be leveraged against predators coming after livestock. The shape of poverty is also very different. Urban poor may use panhandling or dumpster diving to supplement their diet. But rural poor are likely to have a rifle and unlikely to have dumpsters. So, they shoot "critters" by which I mean small game or vermin that can be used to add protein to the diet. Guns in the country are a way of protecting and obtaining food.
So here is my proposal: tax the hell out of urban gun sales and use the money thus obtained to make guns and ammo WIC eligible and tax free in rural areas to rural residents. We don't tax food, and we don't tax seed for food plants. Let's not tax the tools of food protection/acquisition either.