(I realize this post is a bit long - it's something I wrote several years ago at the request of an acquaintance, who sincerely wanted to know why I was so unwaveringly "pro-gun".)
The right for American citizens to bear arms is secured by the Second Amendment to the United States Constitution, adopted in 1791. The founding fathers had struggled under a tyrannical regime and fought a war, and ensured that the citizens of this new country would have the right and the ability to protect and defend themselves. If you've never read the Declaration of Independence and Bill of Rights, I encourage you to do so. Forty years ago my American History teacher reserved every other Friday to read and discuss the Declaration, Constitution, and particularly the Bill of Rights. (Thank you, Mr. West.) I wonder how many of today's teachers find it as relevant. Let's not forget that those men were 'inventing' a form of government unlike anything the world had ever known.
The right to bear arms is so strong because the other nine comprising the Bill of Rights all concern freedom, the judicial process, and the limitations of government. In context, it is exceedingly clear to me what the writers intended with the Second Amendment - and I'm no Constitutional law professor. The Second Amendment was put in place as part of the checks and balances, to ensure that the tyranny of government could not be imposed upon the people, as well as a means to protect one's personal freedom. The formation of our government was a long and laborious process, and the mental aptitude of today's politicians holds no candle to that of the founding fathers. The laws of other nations don't concern me - we have a guaranteed right that citizens of other countries do not possess. By that right, American citizens don't need to justify why they want or need a gun, any more than they must justify why they do or don't exercise their right to vote.
I've been around guns all my life, as a child, as a youth, in the Army, and 30 years since. My father kept loaded guns around the house, and the rule was simple: Those are Daddy's guns. Don't touch them. But early on he taught the six of us to use them safely and responsibly. I was five when I first fired a rifle, with Dad's assistance of course. And I've never murdered anyone. I enjoy guns and shooting and always will, and within me there is no blood lust to murder anyone. But if it comes down to it, I'll defend me and mine, and you and yours, without hesitation.
So to answer your question - I carry a gun because there is a lot of evil in this world. It's a massive list, but I think the mere mention of James Holmes and the Khmer Rouge and the Nazi Party will suffice. I don't intend to die at the hands of some sociopath while thinking, "... I should have had my gun..."
No matter what laws are passed, criminals will always have guns, or pipe bombs, or spears. We cannot legislate evil; we can only fight it, and put it down like a rabid dog. As a "civilized society", ours seems unable to comprehend that evil exists. There is ample footage of the killing fields and the concentration camps; yet somehow people still have a burning desire to rationalize evil - a bad childhood, lost his job, etc. - so they can sleep at night, secure in the delusion that mass murderers are just misunderstood youth or had a good reason to do what they did.
If guns caused violence, there would be no one left in this country, as the millions upon millions of gun owners would have all slaughtered each other and everyone else.
As for gun control ... Let's say the government passes a law strengthening the background check of the mentally ill. This is only the diagnosed, reported component of the mentally ill. So which mental disorders will preclude citizens from being deemed trustworthy with firearms? All of them, I'll wager. This process will require a deeper governmental probe into medical databases, and once that door is unlocked, it cannot be closed. Hmmm, let's have a look here ... Bob suffers from migraines, Sue admits to a few drinks a week, John takes painkillers for his back, Ann has fainting spells ... if armed, they would surely be a danger to others. Those opposed to guns (and, I submit, who also fear a legally armed citizenry) seek any possible means of restricting gun ownership, and who do you think gets to establish the pass/fail standard of being healthy enough to own a gun? Michael Bloomberg, while protected by armed bodyguards, believes that large soft drinks must be regulated by the government. We cannot be trusted with a Big Gulp, so firearms are out of the question, right?
There will always be murders and mass killings, just as there always have been. Progress doesn't magically instigate a transformation in the hearts and minds and souls of men. In 1958 my great-aunt murdered her husband in his sleep by cracking him over the head with a big ceramic dragon, with a loaded revolver right there in the bedside drawer. No gun required. The 2012 FBI crime report shows 8,800 murders with guns, and 3,900 by other means. Roughly one-third of U.S. murderers didn't use a firearm. Without guns, the other two-thirds of our murderers would surely join them and find another means. Evil has existed since the days of Cain and Abel, and countless people were murdered long before the gun was invented. Genghis Khan is said to have taken 40 million lives.
Gun confiscation? Gun registration? Sure, go tell many millions of good ol' boys they need to get in line and hand 'em over, and see what happens. These are punchlines and talking points used by politicians to get elected, then they can blame the NRA (of which I am a proud member) when their idiotic ideas do not come to fruition. All thinking people are appalled by murder, whether they own a gun or not. So any politician claiming to be MORE appalled than others, and grandstanding that gun control will stop murder, is either an idiot or a liar. I put more stock in someone stating we're going to colonize Pluto. I also believe with all my heart that the government couldn't marshal enough soldiers and police officers willing to go door-to-door looking for guns. So if the volunteer Obamajugend come goose-stepping down my strasse, you know where I stand.
I've read an anecdote on several forums and blogs, and I think it was originally credited to a Minnesota State Trooper. He pulled over an elderly lady for a minor violation, and she presented her driver's license along with her carry permit. He asked if she was armed, and she stated there was a .38 in the door pocket. Then she told him she had a .45 in the console, and a shotgun in the trunk.
He was rather taken aback, and asked her, "Ma'am, what are you so scared of?!?"
And she looked him in the eye and calmly answered, "Not a f--kin' thing."