An urban legend making the rounds today is that American manufacturers can’t compete because of high and rising health-care costs. The Big Three auto makers, for example, say that their healthcare costs account for $1,500 of the price of a new car, rendering them helpless in the face of imports from places where health care is paid by government.

The proposed solution: a national healthcare system of our very own.

That may seem like a nonstarter now, but that picture might change dramatically under a President Hillary Clinton. And it would have wide support from certain sectors of American industry. But even if you accept the notion that health-care costs are to blame for American uncompetitiveness, there is ample reason to doubt that national health care, whether designed by Mrs. Clinton or anybody else, would solve the problem.

Indeed, there is reason to think it would make matters worse, perhaps far worse.

For starters, one way or another, somebody has to pay for health care no matter how it is provided. In the case of national health care, it would be the taxpayer, rather than the company or the individual. But wait: Companies and individuals are the taxpayers. And as taxes (or deficits, representing future taxes) rise, the incentives for work, investment, and savings will decline. The result would be lower incomes and wealth – and fewer sales of things like automobiles, especially automobiles that are perceived (rightly or wrongly) to be higher in cost and lower in quality.

The national health-care enthusiasts also reckon without political dynamics. In return for relieving American companies of their health-care costs, Washington is sure to ask for something in return – say, a promise to keep workers on the job or to raise wages or to perform some other presumed good.

Companies would soon find themselves no further ahead financially than when they started. And they would have discovered an old truth: The politicians are far more interested in getting themselves re-elected than in actually solving a problem.

Well, you say, a government-run healthcare system would be a lot more efficient, saving everybody lots of money. Initially, at least, there might be some truth to that. Today’s mixed system – half the health-care budget already is covered by government programs – is a crazy quilt of regulation and insurance paperwork. America today spends 15% of its gross domestic product on health care, far more than the 8-12% common in other major industrial countries.

But much of the higher cost is a result of the fact that Americans are substantially wealthier than the citizens of Europe, Japan, and Canada. As a result, they are simply choosing to buy more health care. Moreover, health costs are exploding just as fast in most other industrial countries, albeit from a lower base, as demand outruns supply. As a result, governments in these countries are being forced to ration available health-care resources by fiat (rather than by price, as in a market system).

Meanwhile, the erosion of economic incentives under a high-tax welfare state has been extracting a heavy price. Japan’s once-miracle economy stopped growing almost a decade ago; European unemployment rates are double those in America. And most medical innovation, with its prospect of better health, is taking place in the United States.

The last bastion of the government healthcare proponents is that health care is a “right.” But even if that’s true – funny that it’s nowhere mentioned in the Bill of Rights – it begs the question of how that right is to be fulfilled. Canadians are flocking to U.S. hospitals to assert their right to health care, for example. And if an economy crashes under the weight of a national health system, what happens to the claims of a right to a job?

For decades, union and management at big companies like General Motors have tried to create their own welfare states. Having failed, they now would like us to believe that what’s needed is an even bigger welfare state. What’s really needed is for American industry to face reality and stop making promises they – and nobody else – can keep.

Mr. Bray is a Detroit News columnist