Over the past half century, the percentage of Black Americans living in the nation’s suburbs has doubled, a shift that is changing the balance of political power in key regions of the country.This transition is simultaneously raising the living standards of better-off African Americans and leaving the poor behind in deteriorating urban neighborhoods.“Since 1970, the share of Black individuals living in suburbs of large cities has risen from 16 to 36 percent,” Alexander W. Bartik and Evan Mast, economists at the University of Illinois and Notre Dame, write in their 2021 paper “Black Suburbanization: Causes and Consequences of a Transformation of American Cities.”“This shift,” they point out, “is as large as the post-World War II wave of the Great Migration.”In contrast, the Black population in “central cities remained flat until 2000 and then declined significantly, leading their share of the national African American total to fall from 41 to 24 percent.” Urban census tracts that were majority Black and had a poverty rate above 20 percent in 1970, according to their data, “have since lost 60 percent of their Black population.”The two authors continue: “Black suburbanization has led to major changes in neighborhoods, accounting for a large share of recent increases in both the average Black individual’s neighborhood quality and within-Black income segregation.”In their paper, Bartik and Mast provide data showing that “suburbanization plays a major role in both rising income segregation within the Black population and a growing divergence in neighborhood quality of Black suburbanites and city dwellers,” which “has increased within-Black stratification due to a lack of low-cost suburban housing and relatively low white flight.”The exodus to the suburbs, according to the two economists,has accounted for most gains in Black households’ neighborhood characteristics, with Black city dwellers in some cases experiencing relative declines. For example, while the neighborhood median income of the average Black individual has modestly improved from 61 to 66 percent of the average White individual’s neighborhood income, the figure has fallen from 58 to 50 percent for Black city dwellers.Bartik and Mast’s analysis confirms the prescient warning of William Julius Wilson, a sociologist at Harvard, who famously wrote in his 1987 book “The Truly Disadvantaged” that before the enactment of fair housing legislation, “lower class, working class and middle class Black families all lived more or less in the same communities, sent their children to the same schools, availed themselves of the same recreational facilities and shopped at the same stores.” The Black middle and working classes “were confined in communities also inhabited by the lower class; their very presence provided stability to inner-city neighborhoods and reinforced and perpetuated mainstream patterns of norms and behaviors.”The impoverished neighborhoods they leave behind now, Wilson continued, “are populated almost exclusively by the most disadvantaged segments of the Black community, that heterogeneous grouping of families and individuals who are outside the mainstream of the American occupational system.”A separate February 2023 study of Black suburbanization, “Racial Diversity and Segregation: Comparing Principal Cities, Inner-Ring Suburbs, Outlying Suburbs, and the Suburban Fringe,” by Daniel T. Lichter, Brian C. Thiede and Matthew M. Brooks of Cornell, Penn State and Florida State, confirmed many of the findings in the Bartik-Mast paper.One of the most striking shifts they report involves the degree of integration:The extraordinary increases in Black, Hispanic and Asian suburbanization since 1990 have changed the racial makeup of suburbia overall. Multiracial diversity is suffusing America’s suburbs as never before. We show, for example, that there is a 53 percent probability today that any two people randomly drawn from inner-ring suburban areas would be from different ethnoracial groups.At the same time, they write, one geographic region of suburbia — the outer rings — stands out from the rest:Not surprisingly, the least diverse part of suburbia is its fringe — formerly rural — counties, where the average likelihood of drawing two people of different races is only 34 percent overall. This finding is consistent with the hypothesis, untested empirically, that the exurbs may be providing “refuge” for suburban Whites fleeing growing racial diversity.Lichter and his co-authors measured different geographic areas from those used by Bartik and Mast, so the numbers vary, but the trends are similar.Lichter, Thiede and Brooks demonstrate that the rapid rate of increase in Black suburbanization between 1990 and 2020 far outpaced that of other demographic groups.In 1990, 33.9 percent of Black Americans in what are known as metropolitan statistical areas lived in the suburbs. By 2020, that grew to 51.2 percent, a 17.3-point shift over the same period; the share of Asian Americans in metropolitan statistical areas living in suburbs grew by 13.2 percentage points; and the share of Hispanics by 13.8 percentage points.While Black and other minority suburbanites have made economic gains, the suburbs, Lichter and his two colleagues argue,are likely to be infused with racial politics over the foreseeable future. School boards and local communities are increasingly divided on issues of inclusion and exclusion, on the racial gerrymandering of municipal and school district boundaries, and on restrictive zoning laws on housing and commercial activities. The suburbs are arguably at the frontline of America’s “diversity explosion,” where economic integration and cultural assimilation occur or are contested.In this context, Lichter, Thiede and Brooks contend:The idea of “melting-pot suburbs,” which signals residential integration, hardly seems apt. To be sure, the largest declines in Black-white segregation over the past decade were found in the suburbs. But any optimism from this result is countered by declines over the last decade in the exposure index between the Black and white populations in both inner-ring and outlying suburbs.What that means, they explain, is thatBlack individuals are no more likely to be living with White neighbors today than in the past. In fact, Black exposure to Whites in the suburbs seems to have declined, at least in those parts of the suburbs where most of the metro Black population lives.They call this — the fact that “declines in Black-white segregation occurred even as Blacks have become less exposed to whites” — a statistical paradox. One reason for it, they write, is “rooted mostly in white depopulation rather than white flight since 2010.”Past declines “in suburban segregation among Hispanics and Asians seem to have stagnated, or even reversed, over the past decade,” Lichter, Thiede and Brooks write.This finding, they continue,is potentially significant because it raises prospects of growing suburban fragmentation and spatial inequality. Suburbs may be less likely than in the past to connote entry into mainstream society or social mobility. Our findings suggest the formation of new ethnoburbs among the Asian and Hispanic populations — perhaps especially among first- and second-generation immigrants.A study of the shifting politics of suburbia from the 1950s to the present, “Not Just White Soccer Moms: Voting in Suburbia in the 2016 and 2020 Elections,” by Ankit Rastogi and Michael Jones-Correa, both at the University of Pennsylvania, found that from the 1950s to the start of the 1990s,Residing in racially homogeneous, middle-class enclaves, White suburban voters embraced a set of policy positions that perpetuated their racial and class position. Since the 1990s, however, the demographics of suburbs have been changing, with consequent political shifts.As a result, by 2020, “suburban voters were more likely to back Biden, the Democratic candidate, than his Republican counterpart Trump.”Why, the authors ask?White suburban precincts showed greater support for Biden in 2020 than for Clinton in 2016. Our analysis indicates, however, that if all suburban voters had voted like white suburbanite precincts, Trump would have carried metropolitan suburbs in 2020.So what saved the day for Biden? “Democrats carried metropolitan suburbs in 2020 because of suburban voters of color.”While suburban whites have moved to the left over the past three decades, there is continuing evidence of white resistance to suburban integration.Erica Frankenberg, Christopher S. Fowler, Sarah Asson and Ruth Krebs Buck, all of Penn State, studied declining white enrollment in public schools in their February 2023 paper, “Demographic and School Attendance Zone Boundary Changes: Montgomery County, Maryland, and Fairfax County, Virginia, Between 1990 and 2010.”They found that from 1990 to 2010, there was “a steep decline in white, school-age children and an increase in Black, Hispanic, and Asian children in both neighborhoods and the schools that serve them,” which, they argue, suggests that “white households reluctant to send their children to diversifying schools are exiting (or never entering) these districts entirely.”The decrease in white students, they write, “may reflect two potential factors: either white families are leaving these public school districts or white households with school-age children are choosing not to enter these districts, perhaps opting for more distant and homogeneous districts.”Along similar lines, Lichter and Domenico Parisi, a sociologist at Stanford, and Michael C. Taquino of Mississippi State examine the response of whites to suburban integration in their 2019 paper, “Remaking Metropolitan America? Residential Mobility and Racial Integration in the Suburbs.”“The exodus of whites,” they write, “is significantly lower in predominantly white suburbs than in places with racially diverse populations. Most suburban whites have mostly white neighbors, a pattern reinforced by white residential mobility.”In addition, they continue, “suburban whites who move tend to choose predominantly white communities with mostly white neighbors.” Affluent whites, they note, are “better positioned to leave diversifying places for mostly white communities with white neighbors.”Their analysis shows that “white mobility rates were lowest in predominantly white places and blocks and highest in suburban places and blocks with significant Black populations.”The rates of white mobility, they add,were especially large if neighbors tended to be Black. Nearly 28 percent of whites moved away from predominantly Black neighbors, compared with an overall average of only 19.25 percent. In suburban blocks with mostly white neighbors, the mobility rate was even lower at 17.45 percent.Even more strikingly, they report:Whites living in predominantly Black blocks are 78 percent more likely to leave the place altogether than move to another block in the same place. Similarly, whites living in places with high concentrations of Blacks are 51 percent more likely to leave the place altogether than move to another block within the same place.A key measure of motivation in deciding to move is the composition of the neighborhood a white family moves to, according to their analysis.“A significant majority of white inter-suburban place moves,” they write,involve movement to predominantly white places (60.1 percent). Only a tiny fraction involved moves to places with predominantly Black populations (7.1 percent). Moves to mixed-race places, however, accounted for a significant minority share of all destinations (32.8 percent).In their conclusion, Parisi, Lichter and Taquino point to the choice of many suburbanizing whites of outer-ring neighborhoods: “Minority suburbanization has been countered demographically by white population shifts between suburban places, to outlying exurban areas and back to the city.”More specifically, they argue, “Our analyses show, at the block level, that suburban whites overwhelmingly have white rather than racially diverse neighbors, regardless of the overall racial composition of the particular suburban place they live.”In addition, “Whites are moving to other suburbs, gentrifying central cities, and exurban fringe areas that seem to set them apart spatially from newly arriving suburban minorities.”Despite the pessimism inherent in their analysis, the authors leave unanswered a question they pose at the end of their article: “Will white suburbanites join the new American racial mosaic? Or instead, will they leave areas of rapid racial and ethnic change, including the suburbs that no longer provide a ‘safe haven’ from racial minorities and immigrants?”From a different vantage point, an analysis of racial “tipping points” — the percentage of minorities in a neighborhood that precipitates rapid declines in the white population — suggests that the threat of white flight in the suburbs may be lessening.In “Beyond Racial Attitudes: The Role of Outside Options in the Dynamics of White Flight,” Peter Q. Blair, a professor of education at Harvard, develops a method for calculating tipping points that shows a steady and significant lessening of opposition to racial integration from 1970 to 2010. “The census tract tipping points,” Blair notes, “have a mean of 15 percent in 1970, 22 percent in 1980, 28 percent in 1990, 36 percent in 2000 and 41 percent in 2010.” He found that the median-tract tipping point also rose, but at a slower pace, from 13 percent in 1970 to 34 percent in 2010.Regionally, the mean tipping point shifted at the slowest pace in the Northeast (9 percent in 1970, 28 percent in 2010) and the Midwest (10 to 24 percent), and fastest in the West (12 to 43) and the South (17 to 41).Blair writes that his data are “consistent with white households becoming more tolerant of living with minorities.”At the same time, race continues to influence housing prices.In a December 2022 paper, “Quantifying Taste-Based Discrimination with Transaction-level Housing Data,” Tin Cheuk Leung, Xiaojin Sun and Kwok Ping Tsang, economists at Wake Forest University, the University of Texas at El Paso and Virginia Tech, explore “the impact of a marginal change of racial composition in a neighborhood by looking at price impacts for transactions that happen immediately after.” They find that “an additional nonwhite household within a radius of 0.2 miles reduces the price appreciation of a house by 0.08 percentage points.”Racial-prejudice effects, they calculate, “translate into a decrease in home value, for a typical house of $380,000 in Virginia, of $3,100 for every ten extra nonwhite neighbors.”These effects are strongest in rich neighborhoods: “The negative effects of a nonwhite neighbor in a rich neighborhood is 0.06 percentage points higher than in a poor neighborhood.”When selling homes, the race and ethnicity of the seller also influences the ultimate price, Leung and his colleagues write: “Compared to white sellers, nonwhite sellers receive significantly less, by more than three percentage points.”Tsang wrote by email, however, that he and his co-authorsdid find some evidence of declining racial prejudice over time. For example, according to our estimates, the price appreciation of a house between its repeated sales would be lower by about 1.1 percentage points for every ten nonwhite neighbors moving into its immediate neighborhood (within 0.2 miles) prior to 2017. After 2017, this number is only 0.65 percentage points.There is a more immediate issue closely tied to the question of whether white racial and ethnic hostility is declining or rising: the 2024 election.Running as an incumbent president, Donald Trump repeatedly sought to exacerbate racial conflict during the 2020 campaign, promising “People living their Suburban Lifestyle Dream,” as he put it in a June 20, 2020, Twitter post, that they would “no longer be bothered or financially hurt by having low income housing built in your neighborhood,” adding, for good measure, that “Your housing prices will go up based on the market, and crime will go down.”Trump’s campaign — based on driving increased racial hostility — did not succeed in 2020, but if he wins the Republican nomination for a third time, no one can predict the mood of the electorate on Nov. 5, 2024. That is especially true in the six to 10 battleground states that will determine the outcome — in a handful of which Trump won and lost by very small margins in both 2016 and 2020.In what may be a sign of lessening racial tension, however, a November 2022 analysis of census data published in The Washington Post — “How Mixed-race Neighborhoods Quietly Became the Norm in the U.S.,” by Ted Mellnik and Andrew Van Dam — reached a striking conclusion:Deep in the bowels of the nation’s 2020 census lurks a quiet milestone: For the first time in modern American history, most White people live in mixed-race neighborhoods. This marks a tectonic shift from just a generation ago.Back in 1990, 78 percent of white people lived in predominantly white neighborhoods, where at least four of every five people were also white. In the 2020 census, that’s plunged to 44 percent.In quite a few states, the change from 1990 to 2020 in the share of the population living in mixed-race neighborhoods is remarkable: Washington went from 14 to 77 percent; Utah, from 5 to 50 percent; Oklahoma, from 31 to 93 percent; and New Jersey, from 26 to 61 percent.America is undergoing a racial and ethnic upheaval that will profoundly shape election outcomes. On first glance, the trends would appear to favor Democrats, but there is no guarantee.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram. More