A new coalition among historic building preservation, environmental protection and city neighborhood movements is in the making. It could be a powerful force to improve our life.

The American way of life is now 80 percent urban, or rather "urbanized." Most of it is lived in amorphous, ill-defined settlements, subdivisions and strip developments, variously called "suburbia," "spread city," "urban sprawl" and "the mess that is manmade America."

Not long ago, all but hopeless mossbacks called this "progress."

The middle-class migration seemed to make old cities obsolete, and they were bulldozed for freeways and "renewed" into high-rise forests.

Eventually, the historic preservationists began to ojbect, because this kind of "progress" destroys handsome old buildings and what was left of charming historic districts.

The environmentalists, or conservationists, began to object because urban sprawl destroys the countryside, encroaches on the wilderness, gobbles energy and rapidly depletes irreplaceable natural resources.

And people who have found a sense of belonging and identity in their neighborhoods -- blacks, Hispanics, ethnics and a pluralistic mix of all of the above -- began to object because "progress" tends to displace them.

In one form or another, all these groups have existed for a long time. But it is only recently that they have become politically active, not to say militant. And it is even more recently that they are getting together.

The first official step in this direction was the formation, last year, of the American Heritage Alliance.

It includes urban planners, archeologists, local and national organizations of historic preservationists, the American the Beautiful Fund, the Conservation Foundation, the Wilderness Society, the Audubon Society, the Sierra Club and some two dozen more.

So far it is only an ad hoc lobbying alliance, formed for the purpose of getting a strong National Heritage Act passed by Congress.

As introduced by Rep. John F. Seiberling (D.-Ohio), this legislation is primarily concerned with historic building preservation, particularly in the states and local communities. But it would also establish state inventories of natural areas, similar to the historic buildings and places register.

The nature conservationists decided to support the urban preservationists this time so they can count on their help the next time nature conservation issues come up on the Hill.

The interest of city neighborhood groups in working with preservationists is obvious. Both groups oppose progress by bulldozer and the preservationists have, in recent years, acquired expertise, public support and political clout in recycling buildings and making neighborhood centers out of old movie houses or railroad stations.

Urban renewal destroyed more homes for the poor than it built. One of the great contributions of the preservation movement is that it taught us to make our existing housing stock livable and desirable.

There are many reasons for the new political cooperation between town and country which is unprecedented in American history:

Young people have a lot to do with it. They have made preservation their cause, much as the civil rights movement, the antiwar movement, the ecology movement were causes of the young. When the good old National Trust for Historic Preservation moved too slowly, too cautiously, too encumbered by establishment concerns, young people here in Washington started their own thing. They shouted "Don't Tear It Down!" And smart young lawyers in their ranks knew how to back up demonstrations with court injunctions -- even on Sunday morning if necessary.

The energy crisis is another, obvious motivation for preservation. Old buildings tend to be better constructed and insulated than the new glass boxes. bThe modern building, furthermore, requires energy for the manufacture and transportation of building materials. More important still, preservation helps to repopulate the cities, and more compact cities reduce the need to consume energy for commuting.

There is the need for jobs, particularly semi-skilled jobs. A recent government study found that, on the national average, a million dollars' worth of demolition of an old building and construction of a new one requires 70 jobs. A million dollars worth of renovation required 109 jobs.

The nostalgia epidemic helps. Much as Alex Haley searched for his "Roots," people everywhere are wondering where they are coming from and begin to appreciate history and historic architecture.

Most of all, a new love for past styles in art and architecture have seized the American soul. In part this may be a reaction to the absence of emotion in cerebral Modernism. But that is not all. We have become too sophisticated to be bamboozled by novelty alone. As an art critic friend confessed to me: "I have seen the past and it works!"

As a citizen movement like this gains momentum, it generates its own generators, as it were, which help to advance and to gain strength. To work its reforms it must have the force to sweep the necessary institutions along.

The most decisive reforms the preservation movement has accomplished are on the local level, where the old buildings are. Some 500 cities and counties have new ordinances to assist preservation. The District of Columbia has a particularly good one.

Until the District preservation ordinance was passed a year or so ago, historic buildings were deemed guilty of obstructing progress unless proven innocent by ardent preservationists. Now a certified building is presumed to be innocent unless its developer-executioner can prove in court that he has no alternative but to do away with it.

The movement got a great legal boost when, in June 1978, the Supreme Court gave broad support to local landmark laws. A developer who wanted to stick an office tower into the old Grand Central railroad station in New York, charged that the city's efforts to stop him were unconstitutional interference with private property rights. The court said it was not.

The decision led to the founding of the National Center for Preservation Law. An effective nonprofit group, headed by Tersh Boasberg, it assists preservationists all over the country to meet legal challenges and to press for better legal protection. Most of the center's work is done by a network of top-notch law firms working pro bono publico.

Another effective group is Preservation Action, headed by Nellie L. Longsworth. Founded five years ago, this is a lobbying group, working for legislation to improve programs, funding and government attitudes.

Facing a backlash against environmental protection, natural resource management and preservation, the budding new coalition is working for a new kind of progress -- progress not only in the pursuit of dollars, but also in the pursuit of human happiness.