Never trust a politician in search of more revenue. Which is essentially every one of them all of the time. Certainly that is the lesson of the Justice Department’s lawsuit against the tobacco industry.

It’s hard to be sympathetic to “Big Tobacco.” The companies profit handsomely from a product that kills. Why shouldn’t the federal government seek reimbursement for costs caused by smoking? “The tobacco companies should answer to the taxpayers for their actions,” argues President Clinton.

His argument is superficially appealing, but he should apply the principle consistently. For instance, poor people get into car accidents and the government pays their medical expenses. Why shouldn’t Chrysler, Ford and General Motors have to reimburse the Medicaid program?

Some people without adequate private health insurance get injured while hang-gliding, rock-climbing, skateboarding, surfing, and engaging in any number of other risky activities. The Justice Department should sue the product manufacturers and property owners.

Moreover, the government covers the medical bills of people who are shot, abuse alcohol, fall off of ladders, get injured playing football, trip down stairs, and suffer heart attacks after a lifetime of eating high-cholesterol foods, red meat and sugar. Washington could fill the courts with reimbursement lawsuits.

However, in all of these cases there is an intervening actor — the injured person. He or she already has a potential cause of action and is entitled to sue. If the “victim” can’t win the case, the federal government shouldn’t be able to do so.

Recovery is often impossible because the person bears substantial if not complete responsibility for the injury. Someone who fails to wear his seatbelt, wants the adrenaline rush of skydiving, enjoys the buzz of drinking, or indulges in a chocolate-full diet can ill complain when injury or death occurs.

So, too, is it with cigarettes. The tobacco industry has won virtually every suit against it. It is hard to demonstrate that cigarettes harm any particular person; while they certainly increase the risk of death, as Robert Levy of the Cato Institute has shown, the numbers are routinely inflated by ignoring the impact of smokers’ other harmful behaviors.

More important, smokers voluntarily assume the risk of smoking. The price of freedom is accepting responsibility for the consequences of one’s actions.

The danger of cigarettes has been known for decades. Moreover, they don’t light themselves and leap into people’s mouths. Quitting can be hard, but people do it every day. In fact, there are nearly as many former smokers as smokers in America today.

There is an even more fundamental objection to the federal lawsuit. It is based on a lie. Smoking does not generate unavoidable, uncompensated costs for government.

First, Washington chose to both provide health coverage for smoking-related illnesses and allow beneficiaries of government programs to smoke, despite the knowledge that doing so would be costly; the government therefore cannot argue the expense was forced on it. (Last summer Congress almost decided to refuse to cover veterans’ smoking-related illnesses.) Having made that choice, Washington should count the bill as an expense of a free society.

Second, government at all levels has been collecting far more than it has been spending as a result of smoking. The costs of smoking are obvious, but most are borne by the individual.

Of course, through government programs the public still pays a substantial amount, but there are counterbalancing cost reductions and revenue collections. The point is, when people die young the government spends less on other, often more expensive, health care treatments, such as nursing care.

The evidence is indisputable. Duke University economist W. Kip Viscusi figures governments at all levels probably save about about 53 cents a pack in net medical expenses. (The overall gain is smaller but still positive after including such factors as lost tax revenue.)

Several other researchers published a study in the New England Journal of Medicine that came to a similar conclusion. They explained: “If people stopped smoking, there would be a savings in health care costs, but only in the short term. Eventually, smoking cessation would lead to increased health care costs.”

Premature deaths from smoking-related ailments are still tragic, of course, but the government’s basic claim, that it is losing money due to smoking, is false. If Washington hasn’t been injured, it isn’t entitled to compensation.

Then there’s the already high tax on cigarettes, averaging almost 53 cents a pack. That is pure government profit.

It’s obviously tempting to say: Let the tobacco industry pay. But constitutional principles as well as corporate revenues are at stake. Legal extortion has no place in a nation that claims to be governed by the rule of law.