Editor's Note: Steve Chapman is on vacation. The following column was originally published in July 2008.

Americans often buy guns for self-defense, a purpose that now has Supreme Court validation. But according to advocates of gun control, those purchasers overlook the people who pose the greatest threat: themselves. Anyone who acquires a firearm, we are told, is inviting a bloody death by suicide.

So says Matthew Miller, a professor at the Harvard School of Public Health. "If you bought a gun today, I could tell you the risk of suicide to you and your family members is going to be two- to tenfold higher over the next 20 years," he told The Washington Post. Since the chance of a gun being used for suicide is so much higher than the chance of it being used to prevent a murder, we would all be better off with fewer firearms around.

It's a rich irony—as though smoke alarms were increasing fire fatalities. But the argument raises two questions: Is it true? And, when it comes to gun control policy, does it matter?

As it turns out, the claims about guns and suicide don't stand up well to scrutiny. A 2004 report by the National Academy of Sciences was doubtful, noting that the alleged association is small and may be illusory.

Florida State University criminologist Gary Kleck says there are at least 13 published studies finding no meaningful connection between the rate of firearms and the rate of suicides. The consensus of experts, he says, is that an increase in gun ownership doesn't raise the number of people who kill themselves—only the number who do it with a gun.

That makes obvious sense. Someone who really wants to commit suicide doesn't need a .38, because alternative methods abound. Gun opponents, however, respond that guns inevitably raise the rate because they're uniquely lethal. Take away the gun, and you greatly increase the chance of survival.

But in his 1997 book, "Targeting Guns: Firearms and Their Control," Kleck points out that "suicide attempts with guns are only slightly more likely to end in death than those involving hanging, carbon monoxide poisoning, or drowning." It's not hard to think of some other pretty foolproof means of self-destruction—such as jumping off a tall (or even not so tall) building, stepping in front of a train or driving at 80 mph into a telephone pole.

People who use guns are generally hellbent on ending their lives. So, deprived of a sidearm, they will no doubt find another reliable method—rather than swallow a dozen aspirin and wake up in the emergency room. Banning guns is no more likely to reduce suicides than banning ice cream is to curb obesity.

A few decades ago, various European countries changed the type of natural gas used for home heating and cooking—replacing a toxic form with a harmless variety. That step eliminated one time-tested way of killing oneself. Alas, while the number of gas suicides declined, in most of these countries, the death toll didn't.

The same pattern holds for guns. The National Academy of Sciences report noted that any link between firearms and suicides "is not found in comparisons across countries." The number of guns in a nation tells you nothing about its suicide rate.

But let's suppose science could establish that people who obtain firearms do indeed increase their death rate (or the death rate of their family members) from suicide. So what?

Buying a car may shorten your lifespan, since traffic accidents are a major killer. Building a backyard swimming pool creates a potential fatal hazard to you and your loved ones. But nobody says the government should interfere with such decisions.

Personal safety is a far more central matter of individual autonomy than those choices. A mentally stable person living in a crime-ridden neighborhood should be free to judge whether she's more at risk from street criminals than from a spell of intense depression.

Presumptuous paternalists argue that Americans should be deprived of guns because gun owners are their own worst enemies. A lot of Americans would reply: We can't trust ourselves, but we can trust you?

Steve Chapman blogs daily at newsblogs.chicagotribune.com/steve_chapman.