Toward the end I noted the knife crime problem that gets so much coverage in Britain. While gun rights proponents sometimes cite this as proof of the futility of banning guns ("they'll just use knives!") in fact the prevalance of knife crime is proof that British gun control is having a useful effect in keeping a bad problem (lots of angry gang affiliated youths) from becomming much worse (lots of angry gang affiliated youths with guns). Let's put this into visual terms because I think it is an important way to think about gun violence once you get past a simplistic binary view of society being criminals versus citizens and all gun problems coming from the former.
A Societal Model
To express this in a crude graphic grouping people into four categeories:
For clarity, by "willing to kill" I mean someone with a general intent or willingness to kill a human, including suicidal people, but not someone who knows they might kill under self-defence or some other justifiable circumstance, but would rather avoid it if possible.
A gun control advocate should want that at least most people be in box 4, with no desire to kill anyone, and no easy means to do so. Box 1 is red for obvious reasons, everyone agrees such people are the biggest danger. Last, they're both yellow but the people in Box 2 (no gun, desire to kill) are of course a bigger concern than those in Box 3 (have gun, no desire to kill), as one can't deny that people with intent to kill will sometimes do so with means other than a gun. People in Box 3 aren't free of problems though, given the greater propensity for lethal accidents in gun-households and of course, many legal guns are stolen from them and then used by people in box 1 to kill with.
The main point here is to say some people will move between boxes in their lifetimes. This is why it makes sense to not only combat the causes of violent crime (move box 1 people to box 3, and box 2 people to box 4) but to reduce the availability of the most lethal means for committing it. People in Boxes 3 and 4 are equally prone to becomming depressed, or being borderline violent personality types that get pushed over some mental limit by a bad divorce or economic distress. In fact, there's some evidence that people with violent tendencies like spouse-abusers will tend to gravitate to Box 3 anyway, but even assuming such people are no more likely than non-abusers to own guns legally, the fact is that a spouse abuser in box 4 who loses his temper completely is much less easily able to murder his wife in a moment of irrational rage. You can't grab your gun and shoot that person you're so red hot angry at if you don't have one. Yes, you can grab a knife or blunt object, but for reasons previously discussed the victim's chances of survival are usually better with any weapon other than a gun.
Gun rights proponents like to draw a bright line between criminals and "law abiding" people, but that's really not how life works. Serious violent crimes are sometimes committed by people who had never previously put a foot wrong. Many gun restrictions may not be as effective when it comes to hardened criminals in Box 1, but that's where a second set of measures designed to keep people out of such life paths would help. As for "responsible gun owners," the research shows they often don't really understand the law that well themselves, and a lot of what they believe are self defensive gun uses turn out to be illegal:
Criminal court judges who read the self-reported accounts of the purported self-defense gun use rated a majority as being illegal, even assuming that the respondent had a permit to own and to carry a gun, and that the respondent had described the event honestly from his own perspective.How many people get guns pointed at them on the highway, or brandished in mall parking space disputes, and the gun owner walks away thinking they've done nothing wrong? If you doubt that, ask yourself if you've ever been cut off in traffic, honked and been given the finger by someone clearly oblivious to the fact that they were in the wrong. People are well known to often judge their own behaviour in the best possible light and it's pretty easy to imagine a gun owner using a gun in a situation that did not legally permit that level of threatened or actual force yet feeling completely justified and in the right. They "felt" threatened, and thus felt justified in what was done to deter that threat, but the subjective feeling of being threatened is not sufficient when it comes to the legal standards required for a violent act of self-defence (which is of course why "Stand Your Ground" laws are popular with gun rights types, a very convenient way to stay "law abiding" is to change the laws to make your unjustified use of force legal). A paranoid person who assumes everyone is about to kill them and responds accordingly would be locked up even through they legitimately and honestly feel their life to be in danger. The perception of threat has to be based on reasonable grounds, which is a nebulous concept, but unfortunately it's what we have.
The stories that came out of the Katrina aftermath were much worse than merely mistaking unthreatening people for threatening. There are evidently some "law abiding gun owners" seemingly waiting for Mad Max to come true so they can set up armed camps and shoot anyone (or anyone not the right skin colour as was sadly the case in Katrina) that approaches the gates. Do these people think of themselves as "criminals"? No, but they became such once they felt order had broken down.
You can't neatly segregate people as "criminals" and "law abiding" as if these were immutable attributes that cannot change through a person's life. It's true that people who earn their incomes legally don't often become "professional" criminals or mobsters, but taxpaying citizens do commit violent crimes. You also can't forget that the problems with guns do not end with deliberate crime, but also includes accidents and suicide. In a trivial way the gun slogan at the top is true, if guns are illegal everyone who has one is de jure a criminal, but it's a trite and glib way to ignore the vast potential upside that comes from a substantial reduction in gun ownership. Keeping guns out of the hands of people in boxes 1 and 2 is vital, but the people in boxes 3 and 4 can move to boxes 1 and 2. I would rather they only moved to box 2 if possible, and so would any gun proponent if you told them the person in question is someone who had a grudge against them personally.
I'm not ignoring the whole issue of legitimate self-defence uses, but that benefit of gun ownership has to be measured against the risks, which gun rights types are generally too willing to ignore. Yes, in boxes 4 and 2 you are at risk of someone in box 1 or 3 using a gun on you and being unable to meet force with force, but your risk of that drops significantly if such people find it more difficult to acquire guns. Meanwhile just because you have a gun doesn't immunize you to gun crime, it only helps if you see it coming and have time to get or pull out your gun. I don't know if any of the victims of the DC Sniper had guns, but it wouldn't have helped any of them if they did. If you're walking down a dark alley and a teenage male is approaching, you might rather be in box 3 at that moment, but you'd rather they were in box 2 or 4. Best for all if you're both in 2 or 4 since you'll both walk away. It's not hypothetical either, Trayvon Martin was in box 4, and if George Zimmerman had been there too, Martin would be alive and none of us would have heard of either person.