Hayley Himmelman and Jasmeen Wellere have several things in common. They’re perceptive, industrious 18-year-olds who just started college. They grew up in the Chicago area and excelled in their high schools. Both were raised in homogeneous communities.

Her parents wanted to live in Glencoe “because it’s such a safe, wonderful community, great education, great people,” Hayley says. “But they said it was a big risk of me turning out to be a selfish, spoiled brat. So they worked really hard to make sure that didn’t happen—that I was privileged in some ways, but wouldn’t be selfish about it. They’d still protect me from certain truths, but they’d also let me know harsh realities, let me see the outside world a little more than other kids here.”

Jasmeen Wellere has experienced harsh realities more directly. She grew up on the south side, in neighborhoods where homelessness and street crime are common. When she was 12, her family was living in an apartment on 82nd, near Woodlawn Avenue. One spring morning she awoke to a chill in the flat—the living room window had been shattered by stray bullets. Gangs were fighting in the neighborhood, and bullets came through the windows on two other occasions that year.

Cook County has the ingredients for rich racial diversity in its schools. In the 2010-2011 school year, the county’s combined enrollment in elementary and high schools was 33 percent Hispanic, 30 percent black, and 30 percent white, according to figures from the National Center for Education Statistics. Subtract the private schools and the enrollment was still tri-ethnic: 36 percent Hispanic, 31 percent black, 26 percent white.

Segregated black and Hispanic schools offer students “profoundly unequal opportunities,” wrote Orfield, who’s been researching school segregation for 40 years. “Millions of black and Latino students, but only a tiny fraction of white and Asian children, go to schools where almost everyone is poor,” he wrote. “More educated and powerful communities almost always win the competition for the most critical limited resources, such as the best teachers and administrators.”

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Segregation also hurts white students. Orfield pointed to census data showing that minorities now constitute a majority of U.S. births. Success as a multiracial nation will entail “learning to work together across lines of race and ethnicity,” he wrote. “Figuring out how to have successful multiracial schools and communities is not a minor concern.”

Research in the 1970s blamed the inferior performance of low-income minority students on their poverty and family background—not their schools. But a meticulous reanalysis of the evidence, published in 2010 in the journal Teachers College Record, strongly indicted segregation. The authors, University of Wisconsin professors Geoffrey D. Borman and Maritza Dowling, found that “going to a high-poverty school or a highly segregated African American school has a profound effect on a student’s achievement outcomes, above and beyond the effect of his or her individual poverty or minority status.” That effect was harmful enough to “deny African American children equality of educational opportunity,” the authors concluded.