It was fortunate, in a way, that alcohol was the target of the first
prohibition effort. Because alcohol is so popular, the damage done by
prohibition efforts was very widespread, and very visible. Because the
use of drugs--especially those, like heroin, for which prohibition
efforts are especially zealous--is less widespread, it has taken longer
for the same effects (or their lack) to be appreciated. More and more
people are coming to recognize by now, however, that prohibition doesn't
work. (It can evidently make a difference on things hardly anybody has
a burning desire to do, like first-class mail delivery. But those are
activities where prohibition is hardly necessary.)
So it's interesting that I don't recall anyone's having raised the
question why we go on expecting prohibitions on murder, rape, or robbery
to work. The answer, obviously, is that they don't either, and this has
been obscured by the fact that those are not activities which large
numbers of people currently want to engage in. Rape may be an
exception, given the high proportion of men (college students, at least)
who say they would do it if they were sure they could get away with it.
But for most of us, the reason we don't kill and steal is not the fear
of getting caught. In a society without a strong social-moral fabric
(usually in the last stages of disintegration), prohibitions won't work;
but in a society where such a structure is intact (not necessarily the
particular moral structure that conservatives are thinking of in this
context), it isn't necessary. In the latter case, it even serves to
undermine intrinsic motivation and our reputation with ourselves, by
promoting the idea that the reason we don't commit crimes is not that
we're good people but that we are simply afraid of getting caught.
Legal prohibitions provide a basis for punishment (or, more
appropriately and effectively, for restitution) in the rare case where a
perpetrator is apprehended, but I don't see much evidence that they are
effective as prevention, for either impulsive or premeditated crimes.
The possible exception of rape points to a serious, long-standing tear
in our social fabric, in the hideous norms of sex-role socialization
which still overwhelmingly prevail in our culture. It would be
interesting to know to what degree that particular disruption of our
civility underlies our general anxiety about people in general getting
out of control.
In the "natural order of things," violence is expensive, for
perpetrators as well as victims (bodyguards, medical treatment, property
damage, etc.). As a way of life, it becomes attractive when costs are
heavily subsidized (an "unnatural order," I would say), as by victim
disarmament (another form of prohibition). Any government violence--the
war on Iraq or on drugs--is of course wholly subsidized, since the
perpetrators bear almost none of the cost themselves.