Reasonable limits are preferable, of course, to unreasonable limits, which is what we'd get if judges who were determined to uphold unconstitutional laws had no such out. Section 1 at least forces them to explain their reasoning. What we find, as in last week's Supreme Court decision striking down the federal ban on tobacco advertising, is often disquieting. Navigating about on a sea of contingency, the judges have all but lost sight of the Charter.

The reasoning of the dissenting minority is lame enough. The federal government had some good purpose in mind when it banned the ads - as opposed to doing it, say, on a dare - and for four of the judges, that was enough. Given the evils of smoking, "an attenuated level of (Section 1) justification is appropriate," wrote Mr. Justice Gerard La Forest for the minority. We needn't insist that the limit be reasonable - just reasonably reasonable. In place of the usual tests of proportionality, minimal impairment and so on, "the Attorney-General need only demonstrate that Parliament had a rational basis for introducing the law," namely "protecting Canadians from the health risks associated with tobacco use." Q.E.D.

But the law doesn't protect Canadians from tobacco use: it protects them from tobacco advertising. For the government to take the extraordinary step of forbidding Canadians from speaking to one another, it must at the very least show there is some harm proceeding directly from the speech itself. Doubtless advertising persuades some people to smoke. You or I might say that is harmful to their health. But what if the smokers themselves disagree?

This principle seems to have eluded even the majority on the Court. For these judges, the critical factor was, as Madam Justice Beverley McLachlin wrote, that "there was no direct evidence of a scientific nature showing a causal link between advertising bans and decrease in tobacco consumption." Banning speech is okay, the judges seemed to suggest, as long as it works.

A less sweeping ban, at any rate - one that applied, say, only to "lifestyle" advertising - might well be a reasonable limit. While it is "a matter of reason and logic that lifestyle advertising is designed to increase consumption," wrote Judge McLachlin, "there is no indication that purely informational advertising would have this effect." It's all right to advertise, in other words, as long as it doesn't work.

Someone has got to stand up for the obvious: that freedom of speech includes persuasive speech, even in noxious causes. Lifestyle advertising is not fraudulent or dishonest. It does not claim to say anything more than it does: Smoking is cool. Well, smoking is cool. It's stupid, but it's unquestionably cool. To deny this is to deny that people drink to have fun at parties - another lifestyle advertising no-no.

If people choose, as millions do, to assume the well-known health risks of smoking, it is not for lack of information: the same information that has persuaded millions of others to quit. It is because they consider the pleasures of smoking are worth the risk of ending their life at an early age, tied to a bed with a tube up their nose. If other people make lots of money convincing them of this, that is a matter for their blackened consciences, not the law.

To say, with Judge La Forest, that tobacco advertising is "far from the core of freedom of expression values" and thus entitled to "a very low degree of protection," is to adopt what the legal theorist Ronald Dworkin has called the instrumental case for free speech: worthy of protection only because it is useful. But this leaves the state in the position of deciding what is useful speech, and the speaker with the onus of proving its utility.

A self-governing people can never accept that burden of proof. The state is our creation, not the contrary. We do not have such rights as it grants us; it has such powers as we give it. It is therefore not the task of the tobacco companies to prove that advertising is useful to society. The state is obliged to prove that it is harmful. The onus on the state here is no less important than the presumption of innocence in criminal trials.

If it is harmful, then intervention is warranted: no right is absolute. If it is not, then the content of the speech is irrelevant. There may be grounds, on this analysis, for regulating the "time and place" of tobacco advertising - to outlaw billboards near schoolgrounds, for example. But that is the limit of what is reasonable.