That is why background checks won't always work.
Background checks aren't (or at least shouldn't be) just about whether or not you have a criminal record. In Canada, you have to get two relatives or close friend to vouch for you before you can obtain a weapon. This is to add a safeguard in order to avoid that someone with mental issues (depression, schizophrenia, anger issues, etc) gets their hands on a firearm precisely for the wrong purposes and becomes a danger for themselves or others.
I've been doing a lot of thinking over the weekend and I thought I'd bring some of my thoughts to this debate... Bear in mind that I don't think guns should be totally outlawed - they're not in a lot of countries, including mine, yet most have stricter laws on the types of guns that can be owned and the conditions of said ownership, and do see a lot less gun violence - I'll let you judge if it's because of such laws or not. I'm just questioning the logic behind wanting to own a gun or not, laws notwithstanding.
"When guns are outlawed, only outlaws will have guns."--Anonymous.
I usually stay cautious around anonymous quotes, and this one might as well come from the NRA. That quote is a fallacy. Law enforcement would still be armed, and they're professionals to whom it is best to leave dealing with criminals.
See, the most common argument I hear for possessing a firearm, outside of hunting, farming and hobbies, is home defence. People will say that having a gun at home makes them feel safe from threats. But what threats are we talking about exactly?
The main reason why someone would want to break into your house is to rob you of your goods. Now here's the thing - the most efficient way to rob you is to wait for a time when you're not home. You'll then have plenty of time to commit your crime. Any smart criminal (or "less dumb than average") knows that, so I'd say most robberies occur when you're not home. So in this case, your gun hasn't protected your property from anything. In fact, it becomes just another one of your goods - and an interesting one at that. Wondering how those illegal guns pop up? The ones with filed-off serial numbers? Ask those who used to have an armory at home then came back from a trip to find out that someone had broken in and made off with all their guns. The fact is, in countries where gun ownership isn't really common, illegal guns are also much less common because they can't be easily found - and thus are also more costly. Simple offer and demand. Of course there are other sources for illegal weapons, but theft still remains an important one.
But then what if the burglar breaks in while you're home, unknowingly or not? And plain old home invasions? The former is probably the most common of both occurrences and you're then dealing with a stupid criminal - and/or one who's completely tripping balls. If he's lucky or any good, you might not even notice he was there until you find your stuff missing the next morning - and then see the above paragraph to know what happens. If he's not, chances are you won't need to go Bruce Willis on him - just hearing a sound or seeing light might very well scare him off. So far, your gun hasn't been necessary. It's either too late to use it, or completely overkill (killing an unarmed man is cowardly, you should know that).
That leaves us with home invasions. Which the media and movies would have us believe is a common occurrence when really it is not. The thing is, they DO happen, but more often then not, they're not random. Think about it, they're extremely violent and planned-out operations - why target any house where there could be absolutely nothing valuable to steal? When you dig a little, you'll find that many home invasion victims are in fact criminals themselves - a lot of such invasions are drug-related. They can also happen when you go around bragging about how you don't trust banks and stashed 300k $ in your mattress - if you're so paranoid about banks, maybe you should also be paranoid about bragging about such things in public. But hey, suppose you do fall victim to a home invasion... and you've got a gun... good for you, right?
Thing is, since everyone in this country has a gun, criminals would be wise to carry a few themselves. And there will be at least two of them, if not three, to stage a home invasion. Three burly guys, armed, and probably high on something that fuels their aggressiveness. So you think you're just gonna go Rambo on them and dispatch them all in a matter of seconds? Yeah, right. A few years ago, there was a campaign in the UK to discourage people from carrying knives for protection. Because, guess what, people were more likely to be involved in a knife fight and get stabbed if they did. The same principle applies to guns.
So these three guys break into your house to rob you. They're completely out of their minds with adrenalin and probably cocaine or methamphetamines, looking to find and subdue everyone in the house. You hear noise and wake up in a jolt, dazed, confused caught off-guard, extremely stressed, and you grab your weapon. What do you think is the likely outcome when two people with firearms and deprived of rational thinking face each other? I'd say a gunfire exchange is pretty likely. Who gets shot first is a toss-up. But if you do manage to take out one of the guys, the other one(s) are going to be pretty pissed, and you and your family are probably toast (if you've got murder one on your hands anyway, might as well not leave any witnesses). And then there's the issue of stray bullets... who knows where or who they'll hit.
I'd really like to see what are the statistics for robberies foiled by an armed citizen VS robberies that ended up in injury or death for an armed citizen. Of course, if you're not armed and a home invasion does happen, you'll likely get roughed up, but if you don't try to pick a fight, you'll probably get to live through it. Just call the cops and let them do their jobs - chances are the idiots will be caught before long. We all know that being a police officers is one of the most dangerous jobs out there, and very few of us would be willing and/or capable of facing the risks they face everyday. So I don't understand how people think that in a stressful situation, they will suddenly master all the skills of a trained police officer and put themselves in the line of fire... that's just a recipe to end up dead IMO.