Many voters across the nation are paying close attention to an issue barely mentioned in the presidential debates: "urban sprawl." Vice President Al Gore has endorsed plans to build more transit lines and encourage "smart growth," and the Sierra Club is running an $8 million ad campaign to support anti-sprawl candidates in key congressional races.

But the concern over sprawl is more than a mere byproduct of increased traffic jams or the loss of open space. It shows that Americans have arrived at a defining moment, where growth is no longer considered a visible sign of social progress but an enemy that must be rolled back or at least stopped in its tracks.

To see the shift, try this experiment: Imagine you could bring back the architects of FDR's New Deal policies. You show them a photo of a new suburban neighborhood and explain that neighborhoods like this are going up all over the country. You add that the homeownership rate in America is near 70 percent - a rate few other nations come close to matching - and that minorities are the fastest-growing demographic group of new homeowners.

At this point, our reincarnated New Dealers would swell with pride and say, "We did it. Our goal of expanding prosperity and extending it to the working class worked." But you quickly correct them: "Oh, no, you don't understand. This is called 'sprawl,' and it's a huge source of controversy. Lots of people want to stop the spread of suburban housing." Your New Dealers undoubtedly would be bewildered.

And who could blame them? In the 1930s, growth was the soul of policy and the challenge of each generation. How would you explain to them, or even to an early Great Society liberal, the controversy of this achievement? The answer can be found in an obscure 1976 book called "Social Limits to Growth" by British economist Fred Hirsch.

Hirsch was writing to refute errors in the then-new "Club of Rome" report, which suggested that Western civilization was pushing the physical limits of growth because of scarce resources, increasing pollution and the fabled "population boom." But though Hirsch disagreed, he did admit that middle-class people might come to doubt the value of economic growth.

This change would occur, Hirsch said, when the link between growth and personal well-being was broken. All of us naturally want more income, more education and more luxuries. This used to mean people were generally pro-growth - which meant, for example, that we were happy to hear about a new factory going up across town. We understood that growth would benefit all, even if we weren't working at the new factory ourselves.

But at some point, that understanding would end, he said. Growing traffic congestion would be one of the first causes of this shift. "Once this growth brings mass consumption to the point where it causes problems of congestion in the widest sense - bluntly, where consumption of jobholding by others tends to crowd you out," Hirsch wrote, "then the key to personal welfare gain is again the ability to stay ahead of the crowd" and oppose change.

If Hirsch is right - if the large scale and fast pace of change is fueling opposition to sprawl - then even the "smart growth" agenda is doomed. Its proponents think they can solve the sprawl problem by getting Americans to live more densely in cities and suburbs (which, given the population projections of the next 20 years, will be a real challenge). But if the mere scale of growth, and not its particular form, is sprawl, then even "smart growth" isn't the answer.

It's possible that certain smart-growth proposals, such as consumer-oriented neo-traditional communities and the revival of main street-style neighborhood centers, will cause some to drop their opposition to "sprawl." But when people say they want growth "controlled" or "managed," they might be using euphemisms meaning they just want it to stop.

There could be a bright future for smart-growth plans that emphasize individual choice and allow the marketplace to create communities of character. But if smart growth merely results in more social engineering, it's easy to predict that this attempt at "suburban renewal" will be a failure as disastrous as that of urban renewal 40 years ago.

This essay by Steven Hayward, a senior fellow at the Pacific Research Institute, is adapted from the Heritage Foundation book "A Guide To Smart Growth"