If you live in a metropolitan area that has adapted well to the post-industrial economy, you have almost certainly noticed a few changes in recent years: high-rise luxury apartment buildings going up downtown, abandoned factories being converted into live/work loft spaces, decayed urban neighborhoods becoming overrun with yuppies. But this is not just the same old gentrification story, going back to the 1970s, of low-income urban neighborhoods with attractive building stock being discovered by artists and, after them, white-collar professionals. New residential buildings are going up in office-only areas that not so long ago turned into ghost towns at night. And it isn’t just happening in the handful of artistic and cultural meccas like New York and San Francisco. Cities from Charlotte, North Carolina, to Houston, Texas, are seeing, and helping, young professionals reinvent their downtowns.

The changes are also occurring beyond city limits. If you live in the suburbs, you may have noticed a totally different demographic trend: the diversifying of suburbia. Maybe it’s the Vietnamese nail salons and pho joints that have filled up the old suburban strip malls, or the sudden emergence of Latino pedestrians walking home along busy roads or congregating in convenience store parking lots. Immigrants and minorities, from the working poor to the affluent, are arriving in suburbia. Some are following job opportunities that have been dispersed around the urban perimeter. Others are priced out of the city. Many are seeking the same virtues—space, good schools, low crime—that drove whites to suburbs throughout the twentieth century.

Alan Ehrenhalt’s new book ties these threads into one common phenomenon that he calls demographic inversion. Our metropolitan areas, he argues in The Great Inversion, are being turned inside out, with the wealthier white people living in the cities, while those who aspire to be the first generation in their family to achieve the American Dream—frequently immigrants and African Americans—move to the suburbs. Ehrenhalt argues that this constitutes a return to form for the modern metropolis, pointing to nineteenth-century Paris and Vienna as cities that invented the template. Major cities in developing countries, such as Buenos Aires and Rio de Janeiro, already fit this mold. In fact, the United States, with the poor in cities and the wealthy in suburbs, has largely been a global exception. But that is ending. “The roles of cities and suburbs will not only change but will very nearly reverse themselves,” he predicts, in about 20 years’ time.

What exactly is different between the gentrification of a generation ago and today’s changes? Now the protean stages are sometimes skipped entirely—the bankers and other professionals aren’t waiting around for artists to walk point for them. They are moving directly into brand new apartment buildings in central business districts. As for the new suburbanites, their migration also represents a historic shift—and a potentially disruptive one. Previously homogeneous communities have become increasingly multicultural, a development that has been welcomed by some in white suburbia and resented by others.

This inversion raises a number of questions. What do the changes mean for the poor, who are being pushed out of cities? Will they be consigned to peripheral areas from which they cannot access professional and educational opportunities without spending increasingly unaffordable sums on gasoline? And will the diversity of urban neighborhoods, always a draw for liberal yuppies, erode over time as more and more of them move into the same areas?

The answer to these questions and others will depend largely on public policy choices. Whether suburbs in general will become more accessible to nondrivers—be they poor, elderly, immigrants, or the disabled—is shaped by policies at the national, state, and local level. The early signs from policy-makers are not promising. Congress recently passed a surface transportation bill that cuts funding for bicycle lanes and sidewalks and gives states more flexibility to focus solely on the construction of new highways at the expense of fixing older roads and improving mass transit. This, of course, is the opposite of what we should be doing to address the trends that Ehrenhalt describes—aging Baby Boomers and young professionals moving to cities to avoid driving, poor people and immigrants who cannot drive or cannot afford cars moving to suburbs. If Ehrenhalt’s book depicts a country undergoing major changes, a glance at our political landscape suggests that our leaders have yet to adjust to the upheaval.

Ehrenhalt is a journalist—editor, for nearly two decades, of Governing magazine, and author of three previous books—and, thankfully, he writes like one. The Great Inversion takes us on a tour of wildly different inner-city neighborhoods (Bushwick, Brooklyn and downtown Phoenix), inner-ring suburbs (Cleveland Heights, Ohio and Stapleton, Colorado), and booming exurbs (Gwinnett County, Georgia). Ehrenhalt doesn’t hide his affinity for the city, and his depiction of the comeback of the American city underscores just how radical the urban revival we all take for granted has been:

American cities all but lost their street life in the last decades of the twentieth century; anybody walking downtown Philadelphia or Boston or Chicago after five in the afternoon found the streets deserted and dangerous. Today, in various forms, street life is returning…. Much of this activity, as in the Paris or Vienna of another time, is clustered around entertainment… And there are cafes. One can make fun of the ubiquitous presence and the uniformity of Starbucks, but the fact remains that just twenty years ago, the idea of coffeehouses in urban centers seemed a quaint vision of the vanished past.

Ehrenhalt’s book enters a debate raging among social scientists in the ten years since Richard Florida published The Rise of the Creative Class: Are cities or suburbs the future? Skeptics of the urban future—Joel Kotkin being the most prominent—are fond of pointing out that most population growth still occurs in the suburbs, an indication that most Americans prefer a suburban lifestyle. Believers in cities and density—including Florida, writers like Slate’s Matthew Yglesias and The Economist’s Ryan Avent, new urbanist architects, environmentalists promoting smart growth, and a smattering of economists such as Edward Glaeser—counter that the high prices in cities that are driving families to suburbs show that demand for walkable urban living exceeds supply. Their case is bolstered by survey data, which tend to demonstrate that roughly one-third of the public desire a walkable urban environment while only about 10 percent of American housing stock meets that definition. Ehrenhalt largely supports their view.

Although he offers plenty of evidence to support his predictions, Ehrenhalt can be prone to a little overstatement. He suggests that by 2020 the southern tip of Manhattan could be “a residential neighborhood with a modest residual presence of financial corporations and financial service jobs.” This sounds impossible: The World Trade Center is reopening between now and then with as much commercial square footage—a gaudy six million—as the old one had. And there is a well-documented trend of less wealthy nonfinancial corporations, such as newspapers and magazines, moving downtown for the cheaper rents. (Last year The New York Daily News moved downtown, and Condé Nast announced that it will be moving from Times Square to the new World Trade Center.)
Another weakness is that while The Great Inversion is an engaging read free of jargon, it is somewhat bloodless in its reportage. Ehrenhalt travels widely and gives accessible, concise summaries of the recent history of the various urban and suburban neighborhoods he discusses. But he does not develop characters, and there aren’t many quotes that sing. The book has color but lacks texture.

This can limit its explanatory power. An essential component of Ehrenhalt’s thesis is that young professionals are more likely to aspire to urban living than were their parents, in part for cultural reasons. But the only guess Ehrenhalt hazards as to why this is so is an offhand observation, which he has repeated in interviews, that millennials grew up watching “Friends,” “Seinfeld” and “Sex And The City.” But, of course, those shows were written because young professionals were already living in Manhattan. If Ehrenhalt had interviewed more early gentrifiers in the neighborhoods he profiles, he might have gained a better understanding of what attracts people to urban neighborhoods besides convenience to work, culture, and nightlife. There is no mention of books, like Suleiman Osman’s The Invention of Brownstone Brooklyn, exploring the cultural roots of the first wave of gentrification, no discussion of the widely dissected hipster aesthetic that prizes urban authenticity over suburban plasticity, no discussion of the rise in popularity of bicycling. For example, he posits that Bushwick’s gentrification proves that urban convenience has trumped aesthetic considerations. But he neglects to discuss why Brooklyn neighborhoods the same distance from downtown Manhattan, but with more attractive streetscapes and housing stock, began gentrifying decades earlier.

Any discussion of our city- and suburban-scapes invariably leads to the most fundamental difference between most American cities and suburbs: The former offer and allow for various modes of travel while the latter are designed entirely for cars. Ehrenhalt is pessimistic on the subject of America’s culture of automobile dependence. While he argues that higher gas prices are a major reason for demographic inversion, he paradoxically believes that new arrivals in cities want to bring the cars of their suburban childhood with them. “My guess is that except in Manhattan, the carless life has yet to achieve any significant traction in the affluent new enclaves of urban America,” he writes. This is a stretch: In the urban neighborhoods with better transit access—such as the inner ring of Brooklyn and Queens and some gentrifying precincts of Washington—many young professionals are foregoing cars in favor of bikes, subways, and buses.

But even when new city dwellers aren’t living car-free, it’s not that they don’t want to. It’s because outside the inner core of half a dozen older major cities, it is virtually impossible to do so. The problem is even worse in the suburbs. A case in point is Buford Highway in Gwinnett County:

Buford Highway, built for automobiles and almost entirely lacking in sidewalks, has ironically grown dense with pedestrians, mostly Asian and Hispanic women who are not afraid to walk long distances down the six-lane road…. The creators of Buford Highway had no interest in making it pedestrian-friendly, but the pedestrians have persevered despite them.

If jobs and cheap housing are to be found in the suburbs, how will poor people get from one to another without a car? It raises the question: Shouldn’t Buford Highway be reconstructed now to safely allow for walking? America has a growing population of nondrivers, and a set of land-use and transportation policies that favor, often even mandate, driving.

How then to tackle the changes that The Great Inversion ably documents? For one thing, we need a national mobility strategy that invests heavily in mass transit, makes streets safe for biking and walking, and links affordable housing to transportation. The Obama Administration has the right idea: The Department of Transportation (DOT) awards grants on a competitive basis to the most innovative, economically efficient, and environmentally sustainable transportation projects through TIGER, the Transportation Investment Generating Economic Recovery discretionary grant program. The DOT is also working with the EPA and the Department of Housing and Urban Development through the Partnership for Sustainable Communities, President Obama’s signature metropolitan policy innovation, which works on linking transportation projects, affordable housing developments and other communal investments.

On a local level, governments should turn their attention to zoning reform. According to Ehrenhalt, creating a more urban experience in hitherto unwalkable suburbs is essential if such places are to remain attractive to young professionals seeking to settle down and raise a family. But many cities, and virtually all suburbs, are mostly zoned to require separate areas for residential and commercial development, excessive parking for homes and businesses, and low density. If suburbs really want to urbanize they will need to change all these rules, so that their streets have apartments above stores and so that buildings interact with the sidewalk. Some suburbs, such as Montgomery County, Maryland, are trying to retrofit their towns accordingly. In North Bethesda, officials are pursuing a plan to replace a mall with a dense, walkable mixed-use area. That might work, whereas just building a few outdoor pedestrian-friendly shopping malls won’t suffice.

The other big challenge during this period of demographic churn is racial and socioeconomic integration. Progressives tend to accept such integration as inherently good, even as most whites—especially conservatives—spent half a century fleeing to the suburbs to avoid it. Now that some significant portion of children raised in the suburbs is coming to cities to experience diversity, it is important for progressives to offer a set of policy responses that can allow transitional neighborhoods to remain diverse. Otherwise they may merely go from nonwhite to white without finding a sustainably diverse equilibrium.

The answer would be a mix of more private-sector flexibility and more public subsidy. Desirable metropolitan areas are becoming obscenely expensive because development is not allowed to create enough supply to keep pace with demand. Zoning changes that allow denser construction would help lower average prices. Another measure to reduce the cost of housing nationally, and to let the market shape the proportion of renters versus owners, would be to eliminate the various tax preferences for home-buying, such as the mortgage interest tax deduction and the partial exemption on capital gains from home sales.

But even lower average prices won’t keep low-income families in Manhattan if they are paying the market rate. This is where the government can, and should, step in. Public housing has gotten a bad rap because of infamous housing projects like Chicago’s Cabrini-Green, which turned into notorious slums. But there have been success stories such as the Pueblo del Sol project in Los Angeles. If public housing is sprinkled throughout more affluent neighborhoods, as it often is in New York, the negative social outcomes associated with concentrated poverty are minimized, even as diversity is preserved. Under President Clinton’s HOPE VI program (which funded the effort to replace the blighted Aliso Village projects with Pueblo del Sol) and Obama’s Choice Neighborhoods initiative, new public housing projects have abandoned the isolated-towers-in-a-park model in favor of dispersal, integration with street life, and investments in necessary complements to low-income housing such as public safety. They have also worked with local governments and private-sector investors in order to have maximum effect. Section 8 vouchers, which allow low-income recipients to rent in regular apartment buildings, are another successful program that should be expanded.

Unfortunately, these ideas have run head-on into the wall of our politics. The amount of money appropriated for smart-growth programs was a pittance even under a Democratic Congress. Republicans, upon taking over the House, have sought to defund these small programs and others in the same sphere, such as the EPA’s Office of Smart Growth. And the new House Republican budget will not sufficiently increase funding for Section 8 to continue assisting all families currently receiving vouchers, much less to help more families.

If Republicans have their way and mass transit and public housing remain underfunded, Ehrenhalt’s predictions may well come true: In a few decades cities will be solely playgrounds for the rich. If cities are dominated by chain stores like Starbucks while the strip malls of suburbia are where one finds cheap Vietnamese restaurants, perhaps the next generation of trendsetters will set out for the ’burbs. Indeed, Ehrenhalt writes about inner-ring suburbs such as Arlington, Virginia, where that process has already begun. Maybe one day creative types will look down their noses from trendily sketchy suburban enclaves at those lame bourgeoisie in the cities.

* Correction: This article originally stated that the Pueblo del Sol housing project is in San Francisco. It is in Los Angeles.