So, depending on timing and demographic circumstances, at least a quarter and perhaps more than a third of all drug buyers would be underage, and there would be a great deal of money to be made by selling to them. The primary source of supply would likely be diversion—adults legally purchasing drugs and selling them to customers below the legal age. The sellers (or middlemen who collected and then resold the legal purchases) would make a profit through marking up or adulterating the drugs, and there might well be turf disputes and hence violence. Some of the dealers and their underage purchasers would be caught, prosecuted, and jailed, and the criminal-justice system would still be burdened with drug arrests. The black market would be altered and diminished, but it would scarcely disappear.

Potential for illegal sales and use extends far beyond minors. Pilots, police officers, fire fighters, drivers of buses, trains, taxis, and ambulances, surgeons, active-duty military personnel, and others whose drug use would jeopardize public safety would be denied access to at least some drugs, and those of them who did take narcotics would be liable to criminal prosecution, as would their suppliers. Pregnant women would also pose a problem. Drugs transmitted to fetuses can cause irreversible and enormously costly harm. Federal and local governments may soon be spending billions of dollars a year just to prepare the impaired children of addicts for kindergarten. Society has the right and the obligation to stop this neurological carnage, both because it cruelly handicaps innocents and because it harms everyone else through higher taxes and health-insurance premiums. Paradoxically, the arguments for controlled legalization might lead to denying alcohol and tobacco to pregnant women along with narcotics. Alcohol and tobacco can also harm fetal development, and several legalization proponents have observed that it is both inconsistent and unwise to treat them as if they were not dangerous because they are legal. If cocaine is denied to pregnant women, why not alcohol too? The point here is simply that every time one makes an exception for good and compelling reasons—every time one accents the “controlled” as opposed to the “legalization” —one creates the likelihood of continued illicit sales and use.

The supposition that this illegal market would be fueled by diversion is well founded historically. There has always been an undercurrent of diversion, especially in the late 1910s and 1920s, when black-market operators like Legs Diamond got their supplies not so much by smuggling as by purchases from legitimate drug companies. One possible solution is to require of all legal purchasers that which is required of newly enrolled methadone patients: consumption of the drug on the premises. Unfortunately, unlike methadone, heroin and cocaine are short-acting, and compulsive users must administer them every few hours or less. The dayrooms of drug-treatment clinics set up in Britain after 1968 to provide heroin maintenance were often clogged with whining addicts. Frustrated and angry, the clinic staffs largely abandoned heroin during the 1970s, switching instead to methadone, which, having the advantages of oral administration and twenty-four-hour duration, is far more suitable for clinic-based distribution. Confining the use of heroin or cocaine or other street drugs to clinics would be a logistical nightmare. But the alternative, take-home supplies, invites illegal sales to excluded groups.

Another historical pattern of black-market activity has been the smuggling of drugs to prisoners. Contraband was one of the reasons the government built specialized narcotic hospitals in Lexington, Kentucky, and Fort Worth, Texas, in the 1930s. Federal wardens wanted to get addicts out of their prisons because they were constantly conniving to obtain smuggled drugs. But when drug-related arrests multiplied after 1965 and the Lexington and Fort Worth facilities were closed, the prisons again filled with inmates eager to obtain drugs. Birch Bayh, chairing a Senate investigation of the matter in 1975, observed that in some institutions young offenders had a more plentiful supply of drugs than they did on the outside.

Since then more jails have been crammed with more prisoners, and these prisoners are more likely than ever to have had a history of drug use. In 1989, 60 to 80 percent of male arrestees in twelve large American cities tested positive for drugs. It is hard to imagine a controlled-legalization system that would permit sales to prisoners. Alcohol, although a legal drug, is not sold licitly in prisons, and for good reason, as more than 40 percent of prisoners were under its influence when they committed their crimes. If drugs are similarly denied to inmates, then the contraband problem will persist. If, moreover, we insist that our nearly three million parolees and probationers remain clean on the theory that drug use aggravates recidivism, the market for illegal sales would be so much the larger. By now the problem should be clear. If drugs are legalized, but not for those under twenty-one, or for public-safety officers, or transport workers, or military personnel, or pregnant women, or prisoners, or probationers, or parolees, or psychotics, or any of several other special groups one could plausibly name, then just exactly who is going to buy them? Noncriminal adults, whose drug use is comparatively low to begin with? Controlled legalization entails a dilemma. To the extent that its controls are enforced, some form of black-market activity will persist. If, on the other hand, its controls are not enforced and drugs are easily diverted to those who are underage or otherwise ineligible, then it is a disguised form of wholesale legalization and as such morally, politically, and economically unacceptable.