The American real-estate industry believed segregation to be a moral principle. As late as 1950, the National Association of Real Estate Boards' code of ethics warned that "a Realtor should never be instrumental in introducing into a neighborhood ... any race or nationality, or any individuals whose presence will clearly be detrimental to property values." A 1943 brochure specified that such potential undesireables might include madams, bootleggers, gangsters - and "a colored man of means who was giving his children a college education and thought they were entitled to live among whites."

The federal government concurred. It was the How Owners' Loan Corporation, not a private trade association, that pioneered the practice of redlining, selectively granting loans and insisting that any property it insured be covered by a restrictive covenant - a clause in the deed forbidding the sale of the property to anyone other than whites. Millions of dollars flowed from tax coffers into segregated white neighborhoods.

"For perhaps the first time, the federal government embraced the discriminatory attitudes of the marketplace," the historian Kenneth R. Jackson wrote in his 1985 book, Crabgrass Frontier, a history of suburbanization. "Previously, prejudices were personalized and individualized; FHA exhorted segregation and enshrined it as public policy. Whole areas of cities were declared ineligible for loan guarantees." Redlining was not officially outlawed until 1968, by the Fair Housing Act. By then the damage was done - and reports of redlining by banks have continued.

Ta-Nehisi Coates