The Democrats, says President Trump, are going to destroy the suburbs.

This is a new theme for Trump — he has tweeted it only a handful of times — and likely inspired by recent polling evidence of a suburban defection from his voter base. So what, exactly, does destroying the suburbs entail?

One feature is the Trump campaign's claim that presumptive Democratic nominee Joe Biden supports "defunding the police," such that when vulnerable elderly women call 911 for rescue from a violent intruder, they won't be helped. In reality, Biden has explicitly rejected defunding cops, and Trump's lies on this subject don't seem to be working.

The more prominent feature of the narrative, then, is about zoning. "Destroying the suburbs" apparently primarily consists of allowing neighborhoods of single-family homes to include duplexes, granny flats, and small "downtown" areas of shops.

Taken at face value, this is a bizarre policy choice for the Republican Party, both in its pre-2016 social conservatism and free-marketism and in its post-2016 Trumpian populism. Upzoning — allowing construction of buildings with more units or more nonresidential units than was previously permitted in a given area — seems like it should fit the GOP agenda.

It's a move toward greater economic freedom and stronger property rights. It can lower housing prices and make homeownership more accessible, especially for young couples who struggle to afford both home and kids. (A brief dig through the archives of the conservative Heritage Foundation turns up years of praise for Houston's unusual lack of zoning restrictions on exactly these grounds, and The American Conservative regularly publishes arguments for upzoning, including advocacy for doing away with single-family zoning altogether.) Also, having a granny flat means you might actually live with your granny, who can pass along familial traditions and help with childcare, a very attractive option amid pandemic. Surely this is the kind of pro-family, even pro-natalist policy Republicans ought to like. Why is Trump railing against it?

The president himself has spoken on zoning only briefly. "The Democrats in D.C. have been and want to, at a much higher level, abolish our beautiful and successful suburbs by placing far-left Washington bureaucrats in charge of local zoning decisions," he said last week. "They are absolutely determined to eliminate single-family zoning, destroy the value of houses and communities already built, just as they have in Minneapolis and other locations that you read about today."

In those remarks and an even shorter comment on the subject three days prior, Trump singled out an Obama-era rule called Affirmatively Furthering Fair Housing (AFFH), which Biden supports and which Trump promised to repeal. That repeal arrived Thursday. The administration characterizes it as a strike for freedom, federalism, and family. It is none of those things.

AFFH didn't "force" municipalities to do anything, as some conservatives have alleged. It mainly set conditions on some federal housing and transportation subsidies. (Suburbia is very subsidy-dependent.) It told local governments that to receive cash from Washington, they'd have to meet certain requirements, most notably ending single-family zoning. But single-family zoning isn't the creature of local self-governance Trump suggests. It originated significantly because of a previous set of conditions for different federal subsidies — subsidies, in fact, introduced by the archetypical Democratic administration: the New Deal-era White House of Franklin Delano Roosevelt.

"[S]ingle-family zoning became the standard for American suburbs during the New Deal when the Roosevelt administration, through various programs such as the Home Owners Loan Corporation, required it for home refinancing assistance," explains Charles Marohn, founder of Strong Towns, a new urbanism advocacy organization. "So, [AFFH said,] suburban governments, you won't get the subsidy this time unless you repeal the regulation we required you to enact decades ago to get the subsidy we were offering back then," he continues. "And we oppose this today because we are conservatives?"

It makes no sense. Repealing AFFH while leaving intact the federal subsidies and the restrictions that single-family zoning imposes on property owners isn't conservative, except in the barest sense of maintaining the status quo. (Even that's a stretch, as arguably AFFH was the status quo.) It is an odd sort of federalism in which Washington encourages local governments to curtail individual liberties. And so far from supporting cash-strapped families by allowing the housing supply to increase, preserving single-family zoning means the government keeps housing prices artificially high.

There's another explanation for Trump's suburb rants, and it isn't really about zoning. After all, if single-family zoning were abolished everywhere immediately, most suburban neighborhoods wouldn't change at all. The built environment wouldn't magically transform from houses to high rises. Areas already developed wouldn't shift toward drastically higher density; at most, they might get a few garage apartments and duplex conversions.

And in those smaller, cheaper units, they might not only get current residents' grandmas. They might get new residents altogether — residents, perhaps, who don't look like their neighbors. Trump's defenders have vehemently objected to any insinuation that racism undergirds their affection for city governments telling people how to use their own land. But the history of single-family zoning is not only a story of subsidies; it's also a story of state segregation.

In addition to being heavily subsidized in both construction and ongoing maintenance, much of suburbia was shaped by 20th-century housing and highway policies that implicitly or, sometimes, explicitly functioned to segregate American homes. "White flight" was not merely an organic movement of private prejudice and social fashion. It was in no small part engineered by federal policies, as Richard Rothstein has meticulously documented in The Color of Law: A Forgotten History of How Our Government Segregated America.

"To prevent lower-income African Americans from living in neighborhoods where middle-class whites resided, local and federal officials began in the 1910s to promote zoning ordinances to reserve middle-class neighborhoods for single-family homes that lower-income families of all races could not afford," Rothstein writes. Some of this was classism, he notes, but some of it was done with "open racial intent." In one example Rothstein cites from St. Louis, a city planner hired in 1916 described zoning to keep "colored people" from moving into "finer residential districts." The zoning ordinance adopted there was race-neutral, but planning commission meetings brazenly debated zoning decisions when white neighborhoods risked being, in their words, "invaded by negroes."

The Obama administration's AFFH rule focused on the residue of that deliberate segregation, and Trump's critique of it hasn't untangled the issue of federal manipulation of local policies from the issue of racist zoning. That makes it plausible to see his talk of single-family zoning as the bastion of suburban integrity as implicitly part of an older tradition of state-enforced racism. It's not unreasonable to wonder if being "invaded by negroes" is what Trump means when he deplores watching a "beautiful suburb ... go to hell."