What do we mean when we call smoking an "addiction," given that most of the addicts seem able to give it up? We mean it's a habit. While it is arguable that tobacco, or rather nicotine, has certain pharmacological and physiological properties that could be defined as "addictive," it is more true to say that some people have addictive personalities: The same substance, in different people, results in entirely different behaviour. Yet that is not how most people understand the term. The prevailing popular view is that addiction is something external to ourselves, a power residing wholly in the thing itself, before which we are helpless.

This deterministic fear helps explain why advocates for a repeal of the laws against drugs, including the current U.S. Surgeon-General, have such a hard time. Even those who might be disposed to decriminalize marijuana usually balk at the harder drugs, such as cocaine and heroin. Why? Because they're so addictive. Libertarians might argue, with Princeton law professor Ethan Nadelmann, that an individual has a right to control her own consciousness, much as she has a right to control her own body. But in most discussions the doctrine of addiction trumps academic notions of free will: These people are junkies, man. They're not in a position to choose. So instead the emphasis is on more prosecutions, longer sentences, and urine tests for bank tellers.

With the U.S. Food and Drug Administration moving to declare nicotine an addictive drug, we seem now to be heading in the same direction with cigarettes: not prohibition, but certainly regulation. Much impetus was added by a previous Surgeon-General's report in 1988, which suggested that cigarettes are as addictive as heroin. No one appears to have considered the corollary: Heroin is no more addictive than cigarettes. In fact, for many people it may be less so. According to a New York Times report, 38 per cent of heroin addicts told researchers that the urge to smoke was as strong as or stronger than the urge to take heroin.

Asked to rank six substances over a range of addictive properties, two experts, Dr. Jack Henningfield of the U.S. National Institute on Drug Abuse and Dr. Neal Benowitz of the University of California at San Francisco, rated nicotine ahead of both heroin and cocaine in the degree of dependence it induces, and about level with cocaine in the severity of its withdrawal symptoms and its tendency to increased tolerance (marijuana finished dead last on most counts, behind even caffeine). So how come one is legal and the others aren't?

This isn't to deny the harmful effects of any of these substances. But surely we can learn more from the success of the campaign against tobacco - just 31 per cent of Canadian adults smoke now, down from more than 50 per cent a generation ago - than from the manifest failure of the war on drugs. It should be evident by now that much of the harm of illegal drugs has more to do with their illegality than with the drugs themselves. It brings otherwise upright citizens into contact with criminals. It prevents abusers from getting treatment. It offers incentives for police corruption. Even the violence we associate with the drug world is rarely committed by someone actually on drugs; it more often stems from the impossibility of enforcing contracts in a trade which, for obvious reasons, is disinclined to take its disputes to court.

Had we gone the prohibition route with cigarettes, we should have all these problems and more; the recent experience with punitively high tobacco taxes was frightening enough. By contrast, the marked decline in smoking over the years is a triumph for the principle of persuasion. While high taxes and social sanctions have played their part, it seems likely that a great many people simply got the message: This stuff isn't good for you. For that is to ask them to make a choice, instead of implying that they have none.