(As before, see the full article for more.)

In ten to twelve states, even law-abiding adults generally can't get licenses to carry concealed handguns. In those states and for those people, stun guns would be the most effective available defensive weapon. In fact, in California and Delaware (except Wilmington), stun guns may indeed be carried even though handguns generally cannot be.

But in the no-stun-gun no-handgun-carry jurisdictions -- Hawaii, Massachusetts, New Jersey, New York, Rhode Island, Wisconsin, Annapolis, Baltimore, the Virgin Islands, Washington, D.C., and Wilmington -- law-abiding citizens are entirely denied the most effective defensive weapons in public. And noncitizens and nonresidents in Massachusetts are denied such weapons, as well as irritant sprays, both in public and at home.

Even in those no-stun-gun jurisdictions (Michigan, Akron, New Orleans, Philadelphia, and South Bend) where handgun carry licenses are generally available, 18-to-20-year-olds are nonetheless not allowed to get such licenses. They are therefore likewise denied both firearms and stun guns in public places. Yet 18-to-20-year-old women need defensive weapons more than most adults do: The average 18-to-24-year-old woman's risk of being raped is 5 times greater than the risk for the average woman age 25 and above.

Legislatures that ban both carrying stun guns and carrying handguns can at least say they are worried about the criminal uses of weapons generally, not just about the rare situations where a stun gun would be misused but a handgun would not be. And indeed stun guns can be used both for crime and for self-defense.

But this is likewise true for the criminal law justification of self-defense: Allowing lethal self-defense lets some deliberate murderers (or people guilty of voluntary or involuntary manslaughter) get away with their crimes by falsely claiming self-defense. The killer is alive, and able to claim he was reacting to a threat from the victim. The victim is dead, and can't rebut the killer's claim. The killer doesn't have to prove the victim had a weapon, since it is enough for him to claim that the victim said something threatening and reached for his pocket. And the prosecution has to disprove the killer's claims beyond a reasonable doubt.

Sometimes the jury will see through the killer's false claims of self-defense, and conclude the claims are false beyond a reasonable doubt. But sometimes it won't, and the killer will be acquitted. And sometimes a killer will be emboldened to kill by the possibility that he might get away on a self-defense theory. The self-defense defense is thus crime-enabling as well as defense-enabling.

So are irritant sprays, which are now legal nearly everywhere in the United States (of course with the narrow exceptions noted above), though they are indeed sometimes used by criminals. So are the skills taught in fighting classes, whether the classes focus on street fighting (such as Krav Maga), Asian martial arts, or boxing. Someone trained in these things can use the skills for crime -- whether robbing someone or just beating someone up -- as well as for lawful self-defense. (Some of the classes also provide physical fitness and recreation, but some, such as Krav Maga, are focused chiefly on self-defense.) Yet these classes are not only lawful, but generally seen as socially valuable.

Among other things, we expect that criminals will already have plenty of tools -- often deadly ones, such as guns and knives -- for committing crimes. The marginal benefit to criminals of fighting skills is thus comparatively small. But the marginal benefit to law-abiding citizens of such skills is quite large, especially if the citizens are barred by law from carrying deadly weapons.

Stun guns and irritant sprays are in this respect much like fighting skills. Such weapons might be more effective than mere unarmed combat for committing crimes. But they are likewise more effective for self-defense. And for some people -- such as the weak, the disabled, or those whose work or family commitments keep them from taking classes -- unarmed self-defense is just not much of an option, while stun guns are.

It seems to me, then, that stun guns and irritant sprays should likewise be allowed. The law rightly values self-defense, which should include effective self-defense. Nonlethal defensive weapons dramatically facilitate self-defense. They also facilitate crime, but comparatively slightly (again, because criminals have access to many other tools, both highly deadly, such as guns and knives, and less deadly, such as blunt weapons), and at a lower level of harm than lethal weapons such as guns and knives. The protection they offer to law-abiding citizens should justify allowing them, despite the modest risk of crime they pose.