Today, Sullum and Stimson present their own frameworks for substance control laws in the U.S. Previously, they compared drug legalization and decriminalization, debated the federal government's authority to raid local marijuana dispensaries, discussed past substance use by successful politicians and addressed drug violence.

Question: What would the ideal U.S. drug policy be? What would you keep and reject from current laws?

The ideal drug policy would apply to the currently illegal intoxicants the same distinctions we routinely apply to alcohol: between children and adults, between use and abuse, between abuse that harms only the user and abuse that harms others.

Selling drugs to minors should remain illegal. But adults should be free to decide for themselves what goes into their bodies, provided they do not violate anyone else's rights in the process.

Under such a policy, some people would use currently illegal drugs to excess, just as some people use alcohol to excess. But judging from history, current patterns of alcohol consumption and data on illegal drug use, the vast majority would not.

Until 1914, opiates, cocaine and cannabis were readily and legally available in the United States over the counter and by mail order. They were incorporated into a wide variety of medicines, tonics and popular beverages. Yet even the highest estimates of addiction in the late 19th and early 20th centuries, offered by people making the case for prohibition, indicate that heavy users represented less than 1% of the population.

In the case of alcohol, moderation is the rule. About 10% of those who have consumed at least one drink in the last year qualify as "heavy users," meaning they've had five or more drinks on the same occasion on each of five or more days in the last month. The government's own survey data indicate that what's true of alcohol is also true of marijuana, cocaine, methamphetamine and even heroin: The vast majority of people who try these drugs do not become addicts. In a legal market, the rate of addiction among users would be, if anything, lower, because the people who are most prone to addiction are probably the ones who are least deterred by prohibition. And before you imagine Americans flocking to crack and heroin the moment prohibition is repealed, consider the fact that these are distinctly minority tastes even among illegal drug users, who overwhelmingly prefer marijuana.

Cully, in your first post you accused me of sidestepping "the issue of morality," so let me be explicit. Psychoactive substances are not inherently good or evil; the morality of drug use depends on how the drug is used, for what purpose and in what context. Unwinding at the end of the day or on the weekend by smoking a little marijuana, for example, is morally indistinguishable from doing the same thing with beer, wine or liquor.

Your parade of horror stories, featuring a president high on heroin during a national crisis, meth-addicted child abusers and stoned school bus drivers, obscures the crucial distinction between use and abuse. We could just as easily have a president who is drunk during a national crisis, an alcoholic who beats his kids or an inebriated bus driver. There are ways to deal with such situations that do not require general prohibition. If a drunk wrecks his personal relationships, he pays a social cost; if he screws up at work, he may lose his job; if he assaults someone or endangers others by driving while intoxicated, he can be arrested. But unless his conduct rises to the level of a crime or tort, the law leaves him alone.

The anecdote about your friend "Bob," the lawyer whose alcohol abuse jeopardized his career, family and health but who "got professional help" and is now "a world-class advocate, father and husband," supports my argument. Would Bob have been better off if he had been arrested for alcohol possession and treated like a criminal?

Jacob Sullum, a senior editor at Reason magazine and a nationally syndicated columnist, is the author of "Saying Yes: In Defense of Drug Use."