The causes of our housing crisis didn’t just happen by accident — they were built on purpose. In the first installment of this series, we saw how misguided government policies have made decent housing unaffordable and unattainable for too many Americans. But to fully understand how we got here, we have to go back to the beginning — to the first zoning law in the United States. It wasn’t about green space or infrastructure. It was about race.

On a warm June day in 1910, a Yale-educated lawyer named George McMechen and his schoolteacher wife moved into their newly purchased home in Baltimore’s Eutaw Place neighborhood. Then all hell broke loose. Local youths rioted in front of their house, smashing every window and skylight. The “problem”? Eutaw Place was an all-white neighborhood — and George and his wife were black.

But what happened to George McMechen was hardly the worst thing that unfolded in Baltimore in 1910. In response to the pleas from white Baltimoreans fearful of what the New York Times labeled “the Negro Invasion,” the city narrowly passed the nation’s first zoning law. From that point on, no black resident could move into a white neighborhood — and, in a cynical hat-tip to equality, vice versa.

The mayor insisted the ordinance was for everyone’s good. It “was not passed in a spirit of race antagonism,” he said, and those who supported it were “the best friends the colored people have.” But it had to be passed, he claimed, because “the white and colored races cannot live in the same block in peace.” Violators faced fines and between 30 days and one year in jail.

George McMechen did not agree. He told the Times that the ordinance “is clearly unconstitutional, unjust and discriminating against the Negro.” While he said he would “vastly prefer living in the midst of my own kind,” he and his wife “merely desired to live in more commodious and comfortable quarters.”

“We certainly have the right,” he said, “as American citizens, to the pursuit of happiness and comfort.”

That was a minority view. The Baltimore ordinance proved wildly popular and was copied in other cities. One such city was Louisville, Kentucky, where the Louisville Times pushed for a similar racial zoning law. When it passed in 1914, black residents and some white business leaders opposed it. What happened next became a landmark moment in public interest lawyering.

A white real estate businessman named Charles Buchanan teamed up with William Warley, the local head of the newly formed NAACP, to challenge the law. They devised a plan: Buchanan would sell a lot to Warley, but the contract had an unusual clause — Warley could back out if he wasn’t allowed to move onto the lot. Both men knew the Louisville ordinance would prevent Warley from moving in. When Warley backed out, Buchanan sued him, claiming the Louisville zoning law was unconstitutional. It was a test case — essentially a “sweetheart” lawsuit — where a white seller, represented by an NAACP lawyer, argued that a law designed to keep blacks out of white neighborhoods was unconstitutional, while the black buyer, head of the local NAACP, defended the law.

The NAACP knew it would be a difficult case. Only 18 years earlier, the Supreme Court endorsed the “separate but equal” doctrine and upheld a Louisiana law requiring railroad cars to be segregated by race. Even more disheartening was the Berea College case from 1908, where the Supreme Court upheld a Kentucky law that forced an integrated Christian College, whose mission was to educate youths of all races, to expel all its black students in the name of segregation.

But the NAACP had one ace card to draw: the Supreme Court respected economic and property rights. A few years earlier, in a controversial decision, the court struck down a wage and hour law for bakeries in New York because that law violated the contract rights of the bakery owner and his employees. Taking the court’s respect for economic rights as its cue, the NAACP told the Supreme Court in the Buchanan case that “restrictions respecting the use of property … must affect all citizens without discrimination.”

The Supreme Court agreed. It held that “this attempt to prevent the alienation (sale) of the property to a person of color … is in direct violation of the fundamental law enacted in the … Constitution, preventing state interference with property rights except by due process of law.”

Racial zoning in America was dead.

At least for a while. As readers will see in the third installment of this series, it took only a few years for local governments to figure out another way to keep poor and working-class families out of white neighborhoods. The tactics changed, but the purpose remained the same.

James Burling is vice president of legal affairs at Pacific Legal Foundation, a nonprofit legal organization that defends Americans’ individual liberty and constitutional rights. He is the author of “Nowhere to Live: The Hidden Story of America’s Housing Crisis.”