The Color of Law: A Forgotten History of How Our Government Segregated America by Richard Rothstein Liveright, 345 pp., $27.95

In 2007 a sharply divided Supreme Court struck down plans to integrate the Seattle and Louisville public schools. Both districts faced the geographic dilemma that confounds most American cities: their neighborhoods were highly segregated by race and therefore so were many of their schools. To compensate, each district occasionally considered a student’s race in making school assignments. Seattle, for instance, used race as a tie-breaking factor in filling some oversubscribed high schools. Across the country, hundreds of districts had similar plans.

Justice Stephen G. Breyer, writing for the court’s liberal wing in the case, Parents Involved in Community Schools v. Seattle School District No. 1, argued that the modest use of race served essential educational and democratic goals and kept faith with the Court’s “finest hour,” its rejection of segregation a half-century earlier in Brown v. Board of Education. But Chief Justice John G. Roberts Jr., representing a conservative plurality, called any weighing of race unconstitutional. “The way to stop discrimination on the basis of race is to stop discriminating on the basis of race,” he wrote. Crucial to his reasoning was the assertion that segregation in Seattle and Louisville was de facto, not de jure—a product of private choices, not state action. Since the state didn’t cause segregation, the state didn’t have to fix it—and couldn’t fix it by sorting students by race.

Richard Rothstein, an education analyst at the left-leaning Economic Policy Institute, thinks John Roberts is a bad historian. The Color of Law, his powerful history of governmental efforts to impose housing segregation, was written in part as a retort. “Residential segregation was created by state action,” he writes, not merely by amorphous “societal” influences. While private discrimination also deserves some share of the blame, Rothstein shows that “racially explicit policies of federal, state, and local governments…segregated every metropolitan area in the United States.” Government agencies used public housing to clear mixed neighborhoods and create segregated ones. Governments built highways as buffers to keep the races apart. They used federal mortgage insurance to usher in an era of suburbanization on the condition that developers keep blacks out. From New Dealers to county sheriffs, government agencies at every level helped impose segregation—not de facto but de jure.

Rothstein calls his story a “forgotten history,” not a hidden one. Indeed, part of the book’s shock is just how explicit the government’s racial engineering often was. The demand for segregation was made plain in workaday documents like the Federal Housing Administration’s Underwriting Manual, which specified that loans should be made in neighborhoods that “continue to be occupied by the same social and racial classes” but not in those vulnerable to…