War That Can't Be Won

[W]hile the empirical evidence on the relationship between gun control and homicide is (at this time at least)  utterly inconclusive, there certainly are policies out there that we have very solid evidence to believe would reduce gun-related homicides very substantially.
The one at the top of the list, in my view, is to legalize recreational drugs such as marijuana and cocaine.
The theory behind this policy prescription is that illegal markets breed competition-driven violence among suppliers by offering the prospect of monopoly profits and by denying them lawful means for enforcing commercial obligations.
The evidence is ample. In addition to empirical studies of drug-law enforcement and crime rates, it includes the marked increase in homicide rates that attended alcohol prohibition and the subsequent, dramatic deline of it after repeal of the 18th Amendment. - Dan Kahan writing on the Cultural Cognition Project.

Found this quote on The Volokh Conspiracy. "The evidence is ample." link goes to The Drug War Heresies on Amazon dot com, where you can buy a good, used copy of the book for a penny (plus shipping, of course) which tells me that it isn't a thriller that will keep you turning the pages long past your bedtime. I found this review on Amazon as well, and I think it is inciteful:

"In Drug War Heresies, Robert J. MacCoun and Peter Reuter ask whether drug prohibition makes sense and whether legalization might achieve a better balancing of the costs and benefits associated with drugs and drug policy. They draw on a broad range of social science literature, and they emphasize the lessons provided both by drug prohibition in other places and by prohibitions of other goods, such as alcohol and prostitution. In discussing this evidence, they raise most of the key issues that should be considered in evaluating drug policy. Their book is an excellent starting point for anyone who wishes to understand the debates about prohibition versus legalization.MacCoun and Reuter make a compelling case that many evils typically attributed to drugs result instead from drug prohibition and its enforcement. According to their analysis, prohibition causes increases in property crime because users face elevated prices; increases in violent crime because traffickers cannot resolve disputes using the courts; diminishments of civil liberties owing to the difficulty of detecting crimes without natural complainants; increases in corruption of police and politicians; disruption of countries that produce coca and opium; diminishments of users' health because of poor quality control; increases in the spread of HIV because of prohibition-induced restrictions on clean needles; excessive restrictions on medical uses of drugs; and reductions in respect for the law bred by widespread violation of prohibition-among other consequences.And yet the authors do not endorse legalization. They find great fault with the heavy emphasis on criminal sanctions in current U.S. prohibition, and they believe substantial deescalation to, say, the level of enforcement in western Europe, Canada, or Australia would diminish many of the harms of prohibition while causing only small increases in drug use. Still, they do not endorse legalization. Why not?Their position rests on four arguments: that moving from weak, European-style prohibition to legalization would produce a substantial increase in drug use; that this increase would be a bad thing; that most of the benefits from legalization are achieved simply by deescalating prohibition; and that the effects of legalization are uncertain.""The authors' basic points move in the right direction. They have done a great service in carefully, honestly, and scientifically considering both theory and evidence on the effects of alternative drug policies. Room remains for reasonable persons to disagree about certain pieces of evidence, but if more persons were to analyze drug policy as dispassionately as MacCoun and Reuter, both drug policy and the country would be in far better shape." - From The Independent Review