Smokers stink. I write that as someone who used to light up once in a while but who doesn t touch cigarettes now, and who wakes up each morning in a cheerful apartment on a tranquil, tree-lined street to a deep breath of... the noxious lung exhaust of a cancer chaser on the sidewalk below.

Reflexively, I'm all for raising cigarette taxes to punishing levels, as a handful of cash-strapped states have done this year and as many are considering. My prejudices aside, however, at a minimum, laws should be just. Ideally, they should do something good. So is raising cigarette taxes a good idea?

Cigarette taxes are sometimes called sin taxes, but the arguments made for them suggest they're Pigovian taxes, named for English economist Arthur Cecil Pigou, who died in 1959. Pigou argued that taxes make markets more efficient in cases where goods produce negative externalities, or societal costs that aren't included in the price consumers pay. Gasoline taxes, for example, put on consumers part of the cost of pollution, thereby "internalizing the externalities," as economists say.

With cigarettes, the negative externalities seem clear. A decade ago, the World Bank put the health-care costs associated with tobacco use at 1.1% of gross domestic product in rich countries, or about one out of every $15 the U.S. spends on health care. The U.S. Centers for Disease Control estimates that smoking-related health problems cost more than $7 per cigarette pack sold in the U.S.

Such estimates are wide open to dispute, however, because of the subjectivity involved in deciding how to do the math. For example, a 2008 study funded by the Dutch Ministry of Health, Welfare and Sports compared the lifetime health-care costs of healthy people, the obese and smokers. Until age 56, the researchers found, the obese cost the most per year in care. After age 56, smokers are costliest. The average lifetime cost, however, is highest for the healthy and lowest for smokers. The reason: Smokers die young.

Sometimes such smoking-isn't-so-bad logic is taken to near-comical limits. "If we are to consider negative externalities, should we not also consider the positive externalities of smoking?" wrote Pierre Lemieux, a conservative member of Canada's parliament, in a 2001 paper challenging the World Bank's math. "The use of tobacco is well known for enhancing meals, friendly conversations, and activities in public places such as shopping centers, office buildings, dance clubs, and lounges."

If taxes are meant to address externalities, policy makers must also consider externalities caused by the taxes themselves. These look largely positive at a glance. For example, in a report earlier this year calling for cigarette tax hikes, Cancer Action Network noted that a $1 per pack increase in Texas in 2007 (to $1.47 from 47 cents) nearly tripled revenues the following year (to $1.5 billion from $523 million), despite a 21% decline in sales. Presumably, that 21% decline is in revenues, not volumes; by my math volumes must have fallen about 8%. Either way, less smoking seems good.

Not everyone quits, however. Of the people who continue to smoke, the poor pay far more tax as a percentage of income than the rich, which makes cigarette taxes highly regressive. Also, there's the matter of clues left in Chicago's parks, and what they're telling us. Chicago charges more in cigarette taxes than surrounding areas. For a study published last month in the American Economic Journal, researchers collected a random sample of littered packs in city parks and found that three-quarters didn't have a Chicago tax stamp -- a "startling degree of tax avoidance," the researchers concluded.

If smokers are driving out of their way to buy cartons, they're producing more car emissions. If they're buying illicit packs from a local fetcher (read: smuggler), they might be funding something worse. A Thursday column in the right-leaning National Review argues that "tobacco-tax-hiking politicians have created a situation in which lighting a cigarette is like igniting the fuse on a bomb." In case you don't speak hyperbole, that translates roughly to profits from cigarette smuggling are used to fund terrorist activities, a thesis argued by Republican members of the U.S. House Committee on Homeland Security in a 2007 paper.

Higher cigarette taxes might be a good idea, but with the numbers available today, one can also make the opposite case. For all we know, the current transfer of wealth from smokers to nonsmokers could already be more than whatever extra amount the wheezers are costing us, offset by the cost of any evils caused by the tax. Sorry, Cancer Action Network. I really do want fewer people to smoke. My advice to you is to complement your tax tactic with a nationwide ad campaign targeting the young, emphasizing the link between smoking and erectile dysfunction. Put up signs in men's restrooms calling cigarettes "impotence sticks" and such. Lots of buzz for the buck there.

Economic realities might render cigarette tax theories moot, of course. States badly need cash, and citizens, quite reasonably, aren't keen on paying more. Fewer than one-quarter of Americans smoke. Not surprisingly, 60% of voters prefer higher cigarette taxes to increases in other taxes or reduced spending on programs.