Millions of students around the US have started autumn with familiar rituals: waiting for absent teachers, flipping through outdated books and watching their peers fall behind in strained, segregated schools that experts warn represent a slow-burning crisis neglected by leaders.

Little has changed since a 2014 report concluded that 60 years after the supreme court declared segregation unconstitutional, major regions of the US have turned away from integration toward deeper inequality, said Gary Orfield, a UCLA professor and co-author of that paper.

The “substantial majority” of black and Latino students are in schools segregated by race and poverty, Orfield said. Such students are being primed by struggling schools for “a downward spiral” in a society that increasingly demands college diplomas.

If this is sustainable then that it’s incompatible with democracy, and spells disaster for the long run Gary Orfield

“If you get in a really poor-performing high school, you probably were in a weak elementary school,” Orfield said.

“Let’s say your family’s poor, and then your chances of going to a really great state university are basically nonexistent. It’s deeply unhealthy for a place where a majority of people are non-white.

“If this is sustainable then it’s incompatible with democracy, and spells disaster for the long run.”

According to the report, black people are most segregated in the north-eastern US, especially in New York, where 65% of black students go to school almost exclusively without white peers.

In the western US, Latinos still largely lack access to mostly white schools, the report adds. In California, where white people are a minority, the average Latino student in a public school has only one to two white classmates.

In the south, where courts and officials worked hardest to desegregate schools and dismantle unconstitutional policies, integration has best endured.

When the civil rights act was passed in 1968, 78% of black students in the south went to intensely segregated schools. By 1991, only 26% of black students were in similar schools, the lowest rate in the US.

But following successive court decisions to roll back desegregation orders, that number has increased to 34%, still the lowest in the US but part of a national retreat toward segregation.

Today, two out of five black and Latino children go to a school that is less than 10% white, said Genevieve Siegel-Hawley, a professor at Virginia Commonwealth University.

Siegel-Hawley stressed the consequences of the situation, noting the large body of research that supports the supreme court’s judgment that segregation itself is “inherently unequal”.

“These school environments are linked to a lot of factors that depress kids’ educations,” Siegel-Hawley said.

She listed the data-backed problems of segregated schools: far fewer resources than most white-majority counterparts, leading to high teacher turnover, less experienced or qualified teachers, less structure, less attention, worse access to opportunities and poorer grades.

Data shows that without a stable curriculum or strong teachers, and often coming from poor homes, students naturally struggle. Segregated schools have high rates of absenteeism as families move; the schools also tend to have stricter rules about testing and discipline, in part as a consequence of decades-long policies about accountability. Students also see friends dropping out at high rates.

Siegel-Hawley said: “And then, with post-secondary education not the norm, you’re much more likely to drop out when you see your friends drop out.

“All of those things look a lot different at segregated schools than at stable, diverse schools or homogenous white schools.”

Conversely, research from the desegregation era found that minority students in integrated schools were able to halve “the race gap” of test scores with remarkable speed, with no change in the scores of white students.

While researchers have relatively little data on modern integration efforts, research such as that of Roslyn Mickelson, a professor at the University of North Carolina at Charlotte, shows that students at diverse schools perform better than those at racially isolated ones, where negative effects accumulate over time.

“Twenty years down the line, unless we have more successfully diverse schools,” Mickelson said, “we’re going to have a population that’s grown up in silos of folk similar to themselves, asked to function in a democratic, multiethnic society that is intimately connected to the rest of the world.

“And they’re not going to have a whole bunch of social, intellectual, language skills to get by.”

Researchers blamed a number of causes for the creeping return of segregation. Presidents since Ronald Reagan have emphasized standardized tests and accountability over integration, for instance, supporting a byzantine array of “choice” schools that can either exacerbate or lessen segregation.

The way to stop discrimination on the basis of race is to stop discriminating on the basis of race Chief Justice John Roberts

Courts have also turned away from integration, and since 1991 have increasingly struck down desegregation orders. In 2007 the issue reached the supreme court, which struck down an integration measure 5-4.

Chief justice John Roberts wrote: “The way to stop discrimination on the basis of race is to stop discriminating on the basis of race.”

Perhaps most importantly, white people resegregated with their feet, moving from suburbs to new enclaves as Latino and black people moved in.

“Residential segregation and school segregation have this reciprocal relationship,” Siegel-Hawley said. “Wealthy families look for good schools, good schools drive up housing prices, exclusionary housing policies price poorer people out.”

In cities and more populated areas, officials often “fragment” districts, she said, dividing up more school districts for smaller areas.

For instance, Long Island, New York has four counties and 127 school districts. Towns within 20 miles of each other can be as segregated as 88% white in one and 65% black in the other, with predictable disparities in wealth.

School district “gerrymandering” does not follow the same rules as voting boundaries – officials can reshape school zones mostly as they like, creating wildly irregular shapes and even unconnected “islands”.

Meredith Richards, a professor at Southern Methodist University, said her research “demonstrates fairly clearly that there is a racial dimension” to the redistricting.

“It’s happening most in suburbs and exurbs, where there’s a lot of rapid racial growth, especially of Hispanic and Asian people,” she said. “It’s also particularly severe in the south, in places where there used to be de jure desegregation.”

Although the hyper-local nature of districting meant many factors affected each case, Richards said a look at “who’s getting zoned out” showed a plain correlation: “Predominantly white districts were zoning in predominantly white students, and zoning out nonwhite students.”

Many researchers, including Orfield and Siegel-Hawley, urge districts to adopt magnet and charter schools with civil rights standards, such as free transportation and outreach, and no admissions provisions such as testing or parental involvement.

They also say that communities still have recourse to action through the courts. For instance, 61 years after it helped defeat segregation in the supreme court, the National Association for the Advancement of Colored People (NAACP) has filed suit in Halifax County, North Carolina.

In Halifax, a population of 7,000 people support three school districts – two mostly black and struggling, the other mostly white – and pay for three superintendents, three school boards and three bus departments.

“That doesn’t even make common sense, much less constitutional sense,” NAACP chapter president William Barber II said.

Barber’s chapter accuses the county board of commissioners, alleging that the county has violated the state constitution’s guarantee of education with “equal opportunities” for every child.

“We believe that the factors of resegregation are undermining the ability of students to receive their constitutional dues,” he said.

“If we pull this out and show this to America, we wouldn’t have people saying: ‘We don’t need Brown anymore or the Civil Rights Act.’ This represents the kind of thing that’s going on across America.”