This month marks the 50th anniversary of the North’s worst episode of school desegregation–related racial violence: Boston’s busing riots. Mobs hurled rocks at buses filled with black students newly assigned to South Boston High School, set on the “heights” of that largely white neighborhood. At the time, and in retrospect, the violence was blamed on the racism of Boston’s “ethnic enclaves.” But to get a fuller picture of the incident—and the factors that laid the groundwork for a crisis that drove most Bostonians of means, white and black, out of the public school system—we should look beyond the schools and the buses, to the public-housing system.

I saw plenty of racial animus while covering the busing crisis and its aftermath for the now-defunct alt-weekly, the Boston Phoenix. The paper’s circulation manager, raised in Charlestown, told me to be wary of “guys with nicknames. Like Knocko. Or Whacko. Or Whitey.” But blaming the Boston’s school-integration crisis entirely on racism fails to acknowledge how the Boston Housing Authority, the city’s public agency, effectively segregated the “projects” by race. The fact that these projects were identifiably white or black led to the racialized school assignments that a federal court eventually found unconstitutional.

Racial segregation had been a fact of life in Boston’s public housing long before 1974. The Bunker Hill project in Charlestown was white; Bromley-Heath in Roxbury was black. Old Harbor village in South Boston was white; Columbia Point, in nearby Dorchester, was black. As a summary of the 1988 NAACP lawsuit challenging the system put it, “People of color were discouraged from applying for public housing in the predominately white neighborhoods of South Boston, Charlestown and East Boston.” This contributed to school segregation, as federal judge Arthur Garrity noted in his desegregation decision: “A substantial correlation exists between racial segregation in Boston public housing and in nearby schools. In 1972, for nine public housing projects which are 80% black, there were 33 schools, all of which are majority non-white.”

Boston was not alone. As much as the city is singled out for racist attitudes, public-housing segregation was—and often remains—the norm across the country. In fact, from the program’s outset during the New Deal, the Roosevelt administration endorsed race-specific public housing. Eleanor Roosevelt cut the ribbon on the Brewster Houses in Detroit—which replaced a thriving black small-business neighborhood with all-black public housing. FDR himself cut the ribbon on all-white Techwood Homes in Atlanta, reinforcing rather than challenging the city’s Jim Crow laws. Black neighborhoods across the U.S. were disproportionately cleared as “slums” and replaced by public housing. By contrast, as Richard Rothstein has pointed out in The Color of Law, federal housing policy favored white suburban homeownership via redlining and other discriminatory practices.

In Boston, school officials reinforced public-housing segregation. As detailed in the landmark Morgan v. Kerrigan suit, the Boston School Committee used “feeder patterns”—assignment preferences for students in specific neighborhoods—to segregate the public schools by race. Had the committee not done so, Columbia Point students would have gone to nearby South Boston High School. Instead, those students were sent across town.

If the BHA hadn’t segregated the projects, history may have unfolded differently. If Columbia Point had been racially more integrated and included families with links to South Boston, the neighborhood and its firebrand champion, Louise Day Hicks, may have objected less vigorously to “feeding” the project’s students to South Boston High School. Of course, the school committee might still have assigned white kids to Southie and black kids to Roxbury; it was quite shameless.

Many individual and political sins precipitated the rocks thrown at South Boston school buses 50 years ago, but it’s worth considering that public housing itself was misguided, and not only in its segregated form. The slum clearance that paved the way for South Boston projects demolished useful private housing. Historic photos of Southie’s “Lower End,” leveled for the projects, show low-rise, four-family brick-and-stucco worker housing that could have been renovated, not demolished—and would likely have been valuable today. One can well imagine small private landlords in the Lower End beginning to rent to minority tenants during the neighborhood’s period of declining population. Beginning in 1968, federal fair-housing law would have protected them. Gradual change would have been far better than an abrupt and wholesale busing program.

Whether in Roxbury or Southie, Chicago’s Bronzeville or Pittsburgh’s Hill District, public-housing authorities engaged in racial segregation, while paying no heed to what social scientists now call “social capital”—the networks of social clubs, churches, and small businesses that were demolished to make way for the projects. South Boston has it gangsters, but, per a Boston College scholarly history, “alongside its churches, dozens of Irish social and charitable organizations flourished in Southie, including eleven chapters of the Ancient Order of Hibernians.”

For all the idealistic intentions and accompanying “slum clearance,” public housing and its segregation set the stage for one of the worst chapters in Boston’s history. The problems that preceded busing—including how black residents generally wanted better schools, not specifically to integrate the academically underwhelming South Boston High School—were not solved by the blunt instrument of desegregation litigation. For that, the city has its public housing to thank.