Obviously guns enable bad things to happen, but they also allow would-be victims to defend themselves. The crucial question becomes: What is the net effect? Do guns deter crime or encourage it? Are more lives saved than lost?

To gun-control proponents, the issue is straightforward: Murders result from unintentional fits of anger that are quickly regretted.

Simply keeping a gun out of someone's reach will save a life. There is the concern that more guns will lead to more accidental deaths.

To those on the other side of the debate, the issue is one of deterrence. Citizens use guns to prevent crimes about five times more frequently than criminals use guns to commit crimes.

Police play an extremely important role in reducing crime, though they almost always arrive at the crime scene after the crime has been committed. When confronted by a criminal, passive behavior, particularly for women, is not the wisest course of action. Indeed, the probability of serious injury from a criminal confrontation is 2.5 times greater for women offering no resistance than for women resisting with a gun.

Despite its ready availability, anecdotal evidence alone cannot resolve this debate. To provide a more systematic answer. I recently analyzed the FBI's crime statistics for all U.S. counties by year from 1977 to 1996 as well as extensive cross-county information on accidental gun deaths and suicides.

The study examined states that adopted so-called "objective" or shall-issue concealed handgun laws, such as the proposed law on which Missourians will soon vote, Proposition B. Thirty-one states now have shall-issue laws, while another 12 permit citizens to carry guns if they can demonstrate a need to public officials.

The findings of the study were dramatic. The more people obtain permits over time, the more violent crime rates decline. For each additional year that these laws are in effect, murders declined by another 3 percent, rapes by 2 percent and robberies by 2 percent.

These are the drops over and above the recent national declines in violent crime - and after the impacts of such things as changing arrest and conviction rates, demographics and other gun control laws have been accounted for.

The reductions in violent crime are greatest in the most crime prone, most urban areas. Women, the elderly and blacks gained by far the most from this ability to protect themselves.

The benefits of concealed handguns are not limited only to those who carry them or use them in self-defense. The fact that these weapons are concealed keeps criminals uncertain as to whether potential victims will be able to defend themselves with lethal force.

With one of the longest training requirements and its high fees, Missouri's proposed law will be among the most restrictive in the nation. The evidence in other states with more lenient requirements indicates that those who go through the permitting process are extremely law-abiding.

Permits are revoked for any reason at only hundredths or thousandths of one percent and most of these revocations have nothing to do with improper use of a firearm. The typical experience mirrors Virginia, where not a single Virginia permit-holder has been involved in violent crime. Indeed, despite millions of people currently holding permits and some states having issued permits for as long as 60 years, not one permit holder has to date been convicted of manslaughter or murder.

Concerns that permit holders would shoot others after traffic accidents or angry-drivers-cut-off-in-traffic shootings have proven to be completely unfounded. Only one single permit holder has ever used a concealed handgun after a traffic accident and that case involved self-defense.

No permit holder has ever killed a police officer. Instead, permit holders have on occasion saved the lives of police officers who were being attacked by criminals. My research has found no evidence that concealed handgun laws caused accidental gun deaths or suicides to increase. To date, I have made my data available to academics at 37 universities.

Everyone who has tried has been able to replicate my findings, and only three have written pieces critical of my general approach.

Although the vast majority of researchers concur that concealed handgun laws significantly deter crime, not even these three critics have argued that the laws increases crime.

Both sides in the gun control debate have their own anecdotal stories, and surely many hypothetical horror stories will be raised before this campaign is through. Fortunately these fears are easily disproved once one looks at the experience in other states. It is the criminals and not law-abiding citizens who should fear a law that allows citizens to defend themselves.