More Guns, Less Crime: Understanding Crime and Gun Control Laws.

• Author: Polsby, Daniel D.

by John R. Lott Jr., Chicago: University of Chicago Press, 225 pages, $23.00

About half the U.S. population lives in one of the 31 states with relatively permissive laws regulating who may carry a concealed firearm. These states range from northern New England (Maine, New Hampshire, Vermont) to the deep South (Mississippi, Alabama, Georgia, Florida), the Piedmont (Virginia, North Carolina) to the Southwest (Oklahoma, Texas), the upper Midwest (the Dakotas) to the Pacific Northwest (Washington). They include urban states (Pennsylvania), suburban states (Connecticut), rural states (West Virginia and Montana), and everything in between. The other half of America's people live in jurisdictions like New York, where access to concealed-carry permits is limited to those who can demonstrate a specific need for potentially deadly self-protection, or Illinois, where no one other than peace officers may carry a gun.

A massive natural experiment is thus under way, one that will ultimately tell us whether liberal gun carrying laws are good or bad policy. The early results are striking. It can no longer be seriously argued that relaxing the rules against concealed carrying of handguns is an invitation to violence, to bloody shootouts over fender-benders or football games. That sort of thing, always rare, is essentially absent from crime statistics, no matter what a state's rules concerning who may carry a gun in public. What's more, it is beginning to look as though, when a state authorizes private persons to carry handguns, it takes an important step toward suppressing serious crime.

What is at issue in gun control debates is people's (mostly untutored) intuitions about which of two conflicting theories of human behavior has the upper hand in the real world. The first of these theories, sometimes called the "instrumentality theory" of lethal outcomes, holds that when firearms are more readily available, offenses such as armed robbery and murder - and impulsive homicides especially - should increase because guns make it easier to commit crimes.

The opposite theory is that of "general deterrence," which can be summed up in one phrase: more guns, less crime. That, not coincidentally, is the title of an important new book by one of America's most resourceful and fearless econometricians, John Lott, who for the last several years has been the John M. Olin Visiting Fellow in Law and Economics at the University of Chicago Law School.

Each of these theories captures a certain amount of reality. We know, for example, that x number of impulsive homicides would not occur in a gun-free world. On the other hand, we also know that the prospect of meeting...