We all know that guns can cost lives because the media repeat this message endlessly, as if we could not figure it out for ourselves. But even someone who reads newspapers regularly and watches numerous television newscasts may never learn that guns also save lives – much less see any hard facts comparing how many lives are lost and how many are saved.But that trade-off is the real issue, not the Second Amendment or the National Rifle Association, which so many in the media obsess about. If guns cost more lives than they save, we can always repeal the Second Amendment. But if guns save more lives than they cost, we need to know that, instead of spending time demonizing the National Rifle Association.The defensive use of guns is usually either not discussed at all in the media or else is depicted as if it means bullets flying in all directions, like the gunfight at the OK Corral. But most defensive uses of guns do not involve actually pulling the trigger.If someone comes at you with a knife and you point a gun at him, he is very unlikely to keep coming, and far more likely to head in the other direction, perhaps in some haste, if he has a brain in his head. Only if he is an idiot are you likely to have to pull the trigger. And if he is an idiot with a knife coming after you, you had better have a trigger to pull.Surveys of American gun owners have found that 4 to 6 percent reported using a gun in self-defense within the previous five years. That is not a very high percentage but, in a country with 300 million people, that works out to hundreds of thousands of defensive uses of guns per year.