AFTER NEARLY a century of ever-intensifying metropolitan growth, American society has begun a march back toward its hinterlands. Reacting to the cacophony of urban life, millions of Americans seem to be succumbing to what may be called the Valhalla syndrome -- a fin de siecle yearning for a heavenly retreat, with the promised reward of a simpler, less complex existence.

This mass migration could well shape the economic, political and cultural landscape of the coming decades. As middle-class, predominately white Americans detach themselves from the multi-colored realities of urban metropolitan regions -- moving not just to the suburbs but far beyond -- the gap between the cities and the world beyond could grow ever greater.

"There's a real growing anti-urbanism out there," observes Ken Johnson, a demographer at Loyola University in Chicago. "People want to be out of the cities and they are now going further and further past the fringes."

Recent demographic data reveal the strength of this trend. After losing population for decades, rural areas are now adding people at three times their 1980s growth rate. Between 1990 and 1994, more than 1.1 million net migrants moved into rural areas and small towns, most of them from suburban or urban locations.

While 1 million people may not seem that significant in a country of over 200 million people, this shift comes on top of an even larger rush into smaller metropolitan regions, particularly in the Intermountain West between the Rockies and Sierras. In this decade, for example, Arizona's and Idaho's populations expanded at nearly three times the national rate -- and Nevada grew at nearly five times the norm -- to be sure, from relatively small bases.

And even in the larger regions, observes John Kasarda, director of the Kenan Institute of Private Enterprise at the University of North Carolina, virtually all population and job growth now takes place in those suburbs most distant from their urban cores. These include people who live in semi-rural locations within commuting distance from the "edge cities" at the periphery of larger metropolitan areas.

"It's not just the old move to the suburbs, it's the exurbs and beyond," Kasarda explains. "It is a move to remove as far as possible from the inner-city poor areas. It's both avoidance and flight."

This "avoidance" also reflects consternation, predominately among whites (but also some blacks) about the changing demographics of such large metropolitan regions as Los Angeles, San Francisco, New York and Chicago, which have received the vast majority of new immigrants. People who grew up in these areas are often unhappy to find their old neighborhoods and industries dominated by newcomers from Latin America, Asia and the Middle East.

Most spectacular has been the mass migration from New York and other parts of the Northeast. From 1990 to 1994, the New York City area suffered a net domestic outmigration of more than 861,000. Taken together, the Northeast lost over 1.5 million people to other areas, largely to heavily white enclaves such as central Florida, the southern Appalachian hill country as well as the edge cities around the Research Triangle in North Carolina and Atlanta.

Corporations too have been infected with the Valhalla syndrome. Seeking lower costs, less regulation and cheaper housing for their employees, the fastest-growing areas for corporate relocations and expansions have been in places such as Lancaster, Pa., or Huntsville, Ala., or in smaller cities such as Orlando, Austin or Nashville and in the Salt Lake valley.

Like the new migrants, many relocating executives openly express the desire to be in a region with a highly homogenous, relatively well-educated work force. "One thing people don't want to worry about is race relations," notes Brad Bertoch, president of the Wayne Brown Institute, an organization dedicated to developing Utah's high-tech industries. "Companies think if they go to a neighborhood where everyone is like me, it makes it easier. It takes away from stress. People want to remove some of the variables of their lives."

In many ways, the current Valhallan movement reflects deep-seated historical tendencies within the American character. From Thomas Jefferson to William Jennings Bryan, anti-urbanism has been a mainstay of American political thought. It was only during the New Deal, led and conceptualized largely by urbanites, that cities such as New York began to move from exceptions to trend-setters.

Yet the era of intense urbanization began to peter out by the late 1950s as millions of largely middle-class Americans left old urban neighborhoods for the suburban rings around them. Although some large cities, such as Los Angeles and Boston, boomed during the 1980s, the overall trend for urban areas has been largely negative, with the nation's central cities' share of U.S. poverty growing from 27 percent in 1960 to roughly 43 percent today.

In part, observes author George Gilder, the growth of rural areas is being powered by new communications technologies -- the Internet, video conferencing, expanded computer processing power -- which have all but obviated the need for cities. Urban areas, he suggests, are little more than "leftover baggage from the industrial era." The new America will be born in the former hinterlands, far from the masses of immigrants, inner city blacks, gays and other encumbrances. "Cities," Gilder notes, "are dirty, dangerous and pestilential."

Although technology may be making the Valhallan trend possible, the shift should not be seen primarily as an economic phenomenon. It is first, and foremost, a cultural movement back to an earlier, perhaps largely imagined past of small towns, safe streets, clean air and common cultural values. As Larry EchoHawk, a Democrat who lost his 1994 bid for the governor's job in Idaho, puts it: "Idaho is what America once was, and what the rest of the nation now wants to be."

Unlike the traditional Sun Belt ascendancy of the 1960s and 1970s, the Valhallans are more ambivalent about turning their regions into powerful, new competitive centers. With their eyes on restoring this supposed idyllic past, the bulk of the newcomers to the Valhallas do not tend to be the young and aggressive pioneering types who, in earlier decades, migrated to regions such as Los Angeles, Houston or San Jose.

The new migrants, notes William Frey, a demographer at the University of Michigan, tend to be older, less affluent and less well educated, and often close to retirement age. Roughly one fourth of people moving into Colorado, for example, are over 55; the migration has been so much older than predicted that the anticipated pressure on many school districts there has not materialized.

Since they are largely seeking to escape urban America, many Valhallan emigres disdain anything that might bring along the much-feared ills of city life, notes Phil Burgess, president of the Denver-based Center for the New West. Indeed, according to one recent poll, 73 percent of Coloradans felt their state's population and economy was growing too fast. This may well explain why the preponderance of the country's fastest-growing firms remain concentrated in places such as California rather than Utah or North Carolina.

This rural population shift is also having an impact on the political arena. Traditionally, political scientists have thought the migration of Easterners to the South or Californians to the Intermountain West would bring a more centrist or even left-wing political flavor to those conservative strongholds. With their urban sensibilities, the thinking went, they would help "tame" the traditional conservatism of these regions.

Although this has occurred in some areas -- such as Santa Fe, N.M., Burlington, Vt., and Boulder, Colo. -- the Valhallan aspirations of the newcomers has more often strengthened the right's dominance. Indeed the entire Northwestern region, as well as Arizona, has become something of a bastion for all sorts of far-right, antisemitic and anti-black organizations. For one thing, the monolithic nature of places such as Kootenai County, Idaho -- best known for the resort town of Coeur d'Alene -- appeals to those who wish to escape diversity; in 1990, the county had only 139 African Americans out of a total population of 80,000. Idaho has also become the base camp for survivalist developments organized by ex-Green Beret Bo Gritz, who is building his own subdivisions -- with the names "Almost Heaven" and "Shenandoah" -- for like-minded ex-urbanites.

Similarly, in recent years Colorado Springs has become a hotbed for right-wing Christian organizations and the national epicenter for anti-gay movements. Today the city of 300,000 has more than 50 national Christian religious groups; nearly half have arrived in the last decade, including the Rev. James Dobson's Focus on the Family, which moved there in 1991 from increasingly diverse suburban Los Angeles.

The Valhallan movement has also boosted more conventional, right-wing enclaves. For example, according to Raleigh-based political analyst Seth Effron, migrants to North Carolina -- mostly from the Northeast and Midwest -- have been critical to boosting politicians such as Sen. Jesse Helms (R-N.C.).

Much the same process can be seen in the Intermountain West, where a once thriving two-party system has given way to almost total domination by conservative Republicans. States like Idaho used to occasionally elect liberal Democrats. But liberals from the state have far worse prospects today. Newcomers to Spokane, Wash. -- both from the Puget Sound region and California -- played a critical role in defeating House Speaker Tom Foley in his re-election bid last year, though liberal Democrat Ron Wyden did manage later to squeak into Bob Packwood's old seat.

In the past, even right-leaning Utah would back moderate Democrat Scott Matheson. But today's flood of in-migrants, notes the Wayne Brown Institute's Bertoch, have tipped the scales distinctly toward the right. Utah's politics, like that in North Carolina, Idaho and other Valhallan states, reflect more a conservative monoculture than at any time in recent history.

"You think you're getting liberals going out here but for every one liberal you're getting 20 conservatives," Bertoch says.

In the next century, the impact of the Valhallan syndrome may be even more profound. For one thing, current migration patterns virtually guarantee a growing racial and cultural chasm between the cosmopolitan cities and the Valhallan hinterland on a scale not seen since the divisions that led to the Civil War.

By 2020, according to projections by the University of Michigan's Frey, the country will be divided into distinctly ethno-cultural regions. In 12 states -- mostly in the Plains, upper New England and the Intermountain West -- more than 80 percent of youngsters under 17 will be white, while in another 12, including California, Texas and most Northeastern states, young whites will be in a distinct minority.

Much of this is a direct result of the immigration and trade patterns that have emerged since the 1970s. Asians will be a powerful presence in states such as Hawaii, where they will be the largest group, and California, where they will constitute one in five youngsters, but barely register above 5 percent in most other states. Similarly, Latinos will be the largest grouping in California, Texas and New Mexico but well under 10 percent of the population through much of the rest of the country.

It is unlikely -- barring a total dystopian collapse -- that the great metropolitan regions will lose their place completely: They will still be the incubators of America's commercial, technological and artistic cutting edge. For one thing, virtually all the top 10 graduate departments in the sciences and engineering are located either on the West Coast or in the upper Midwest or Northeast. Millions may have moved to the Valhallas, but the intellectual capital of the nation remains very much fixed on the coasts.

Similarly, most of the nation's key exporting industries are also located in urban regions. In terms of global competition, Hollywood, Wall Street and Silicon Valley will not easily be displaced by the likes of Boise, Idaho, or Provo, Utah, much less the even more remote Valhallas.

Yet it may well be that over the coming years these cosmopolitan centers will find their political interests, on economic and social issues, sacrificed by the rising power of the Valhallan regions. Like the struggle between the rural south and urbanized north of the last century, this conflict between Valhallan and cosmopolitan visions will likely shape the America of the next century. Ultimately it may determine whether this society meets the challenge of becoming a harbinger of a new world culture, or whether it will seek to freeze itself, like other declining civilizations, in the comforting outlines of its imagined past. Joel Kotkin is a senior fellow with the Pepperdine Institute for Public Policy and the Pacific Research Institute.