In Paige Glotzer's How the Suburbs Were Segregated, she spends a long time laying out how from the 1890s through the 1960s land developers created, perpetuated, and encouraged the use of restrictive covenants to determine who could move into one of the new Suburban neighborhoods that began popping up at the end of the 19th century. She talks about how these developers, and the professionalized Real Estate industry baked into the structure of the American landscape racist and prejudicial ideas, laws, and enforcement norms which have continued to shape our world today.

Glotzer traces the history of a British capital investment firm creating and backing a new development company in Baltimore, MD. This company, the Roland Park Company, set out intentionally in the 1890s to build one of the first planned suburban communities in the world just outside the Baltimore City limits. City centers were dirty, busy, noisy places as livestock rendering and butchering plants sat next to industrial factories, residential apartments, and commercial businesses. This was a time of scientific discovery and there was a craze to sanitize everything now that the cause of sickness was better understood. Products would be sold, advertised as the "Sanitary" option like how a decade ago everything was HD to ride the craze brought about by new 720 and 1080 resolution TVs. Cities were seen as unclean and unsanitary so the first, biggest pitch for this new development would be its physical removal from the city that would herald its cleanliness.

There was another element wrapped up in this sanitation craze: Racial theories of biology and human existence were still very much in fashion and it was believed that some races were naturally cleaner than others. White people are white after-all, a color associated with purity and cleanliness, while Blacks were dirty colored and lived in squalor. By moving to the Suburbs you were not only doing the right thing for your family's health, getting away from industry and the bustle, but also away from dirty, dangerous elements like Blacks and Minorities. The Roland Park Company's sales material proudly boasted of its restrictive covenant prohibiting the purchase and possession of land by "undesirable neighbors" [Jews who were not sufficiently White enough, Blacks, Immigrants, poor Whites, Catholics, etc).

Realtors at this time were seen as conmen and it was very rare to find one with a good reputation. Following the trend of many professions, the real estate industry and related professions created an organization that would publish standards of practice, ethical rules for conducting business, and provide a publication in which members could propose and discuss new ideas. Anyone who followed these rules, and paid their dues, had the right to call themselves a Realtor, with a capitol R. Developers, companies and people who bought up large tracts of land to turn around into usable property, were included in this organization, the National Association of Real Estate Exchanges.

Realtors and Developers worked hand in hand to create properties the people wanted to buy and how best to sell them. The Roland Park Company's wild success outside Baltimore inspired other companies to adopt their same covenant, often word for word, for their own communities. This began the White Flight from inner cities to the suburbs. Because of the restrictive covenants Blacks could not buy property in these places, even if they had the money in hand. The Supreme Court of the Maryland ruled in 1922 that municipal governments could not enforce segregating housing codes or agreements, nor deny services to communities that were Black or non-White. Roland Park, and others, then turned their covenants into Private Contracts so that every potential buyer had to be approved by existing residents which had the same effect of prohibiting the settlement of "undesirable neighbors". As Realtors professionalized their advice was sought by State and the Federal Government in drafting zoning, redevelopment laws, and codes for building. In many cases, the people working for the developers also had full time jobs or consulting gigs with the governments they were working for, ensuring that the big developers got their way in the new laws that came about in the 1920s during the Progressive Era.

It was taken as common knowledge at this time that Black residents lowered property values by way of merely existing. It did not matter how affluent or established they were, Black neighbors were thought to lower property values and bring on the eventual ruin of once proud neighborhoods. In the case of Baltimore, property laws and tenant housing regulations encouraged the subdivision of urban plots into long thin strips, giving rise to the image of Baltimore's long lanes of beautiful old townhomes. Many of these buildings had been sold or leased to affluent White residents in the 19th century but as they moved out, they were occupied and leased to Blacks instead. These renters, like all renters, did not have the means or the motivation to maintain and upkeep these buildings, and neither did the owners, so these proud homes gradually fell into disrepair and ruin. Anyone could point to this same trend, all over the US, and proclaim with certainty that Black neighbors were no good for respectable property owners.

Cities in the 1930s and 40s, in an attempt to put men to work during the Depression, set about to clean up those areas they deemed "blighted". A Blighted neighborhood was officially a neighborhood that fell under expected norms of upkeep and appearance, and/or had a sizeable infiltration of undesirables into what had formerly been a non-blighted [sic: all-White] community. Infiltration, by the way, was the technical term used. Any neighborhood that had a sizeable Black or minority population was targeted for Redevelopment. Cities would repossess entire blocks and divisions of neighborhoods by means of eminent domain, and then bulldoze everything. Proclaiming that these redevelopments were civic renewal programs, these sites were replaced by theaters and performance spaces, parks and community centers. This displaced the few property owning Blacks in the city cores of major American urban centers to the advantage of affluent and work-commuting Whites.

With developers building communities for Whites only, government regulation creating and encouraging Redlining (the practice of denying loans or sales to individuals beyond arbitrarily drawn borders on municipal maps), and fewer and fewer Blacks owning property it became nearly impossible for poor Blacks to be upwardly mobile and develop generational wealth. They were just about confined to low income, dense rental housing situations where crime would soon blossom. Crime, already associated with Blackness, would become the dog-whistle reason for the segregation of good people [read: Whites] and the poor masses.

In mid to late 20th century NYC you have the result of all this structural racism. Poor Blacks living in poorly maintained Project Housing and Rental Properties that are not maintained by the owners or the municipal government. High rates of poverty leads to high rates of crime, low property rates mean less tax funding to schools and social services, and the abandonment of the City Cores by affluent Whites meant the redirection of Government funds and attention to more upstanding areas of town. Its said that owners of apartment buildings, recognizing that the insurance on their building was worth more than the rent they collected, and would set fire to them secretly to collect on their policy.

I can't speak so much to how this was turned around in NYC definitively but I can say that the Fair Housing Act of 1968 made it illegal for governments and private parties to discriminate against buyers based on Race, Ethnicity, Religion, or Place of Origin. Enforcement of this would take some time to root itself, and would be one of the early things that would get a NYC Realtor and Developer named Donald Trump in trouble in the 70s. Rudy Giuliani ran for Mayor of NYC in 1993 on a platform of cleaning the city up (literally: pick up the trash, renovate the parts of town in bad shape, and take out the human refuse). He said he would be 'tough on crime', another long time dog-whistle for 'tough on Blacks' [who are prone to criminality]. The Broken Window Theory came out of the heritage of structural racism I detailed above; by enforcing building codes and building appearances it was thought that crime was discouraged and undesirable elements pushed away. In practice its the same redevelopment scheme from the first half of the 20th century.

If you have the time, I highly recommend this book. Its not terribly long or dense but it lays out the history, and global interconnectivity, of racism in real estate development and sales that has shaped our modern world.