The US has a long history of discriminatory housing policies, which has entrenched communities of color in poor neighborhoods.

And the one tool the federal government has to push back against these segregation patterns is the Fair Housing Act — specifically the part that says local communities that receive federal funds for affordable housing must “affirmatively further” fair housing. But for much of the law’s lifetime, advocates say it has been toothless.

So two years ago, the Obama administration tackled this issue by creating a new rule that leveraged the growing amount of racial disparity data. This helped communities see invisible trends to set and meet fair housing goals, while also giving the feds a way to enforce the law.

This has irked Republicans, who say this is essentially the federal involvement meddling in local zoning issues. Some, including Trump’s pick for the Department of Housing and Urban Development (HUD), Ben Carson, go further and call this “social engineering.” Rep. Paul Gosar (R-AZ) said this was President Obama forcing "his utopian ideology on American communities."

So Gosar, along with Republican Sens. Mike Lee and Marco Rubio, introduced a bill, dubbed the Local Zoning Decisions Protection Act of 2017, that would roll back President Obama’s legacy on fair housing. Then it bars any similar rules from being created in the future.

But then it goes further.

The clever way Republicans are rolling back Obama’s efforts, and then some

Given the importance of data in Obama’s fair housing rule, Republican lawmakers found a clever way to completely kick the legs out from under his initiatives:

Notwithstanding any other provision of law, no Federal funds may be used to design, build, maintain, utilize, or provide access to a Federal database of geospatial information on community racial disparities or disparities in access to affordable housing.

There is sweeping language in the bill that scares a broad range of people because it could undermine all federal geospatial data. But to be clear, both Lee’s and Gosar’s offices told me they’d be willing to focus the language so it doesn’t do that.

Rather, their goal is to prevent the federal government from using racial disparity data to “blackmail local governments into changing their zoning laws,” said Lee’s spokesperson Conn Carroll. Gosar’s communications director, Steven Smith, told me they want to “prevent the creation” of another custom data tool that pushes federal mandates on local zoning laws.

But in addition to that, Carroll said the data section would ensure the federal government can’t use racial disparity data to threaten local communities with a Fair Housing Act violation. This is important because the Supreme Court recently affirmed that you can prove violations by showing that a community’s decisions had a “disparate impact” on a protected class of people. In other words, you don’t have to prove that a policy was intentionally discriminatory; you can just show its impact using data.

"Data is really the way in which these institutions are held accountable, both in the courts and political processes," said Megan Haberle, who focuses on housing policy at the Poverty and Race Research Council. "So [this bill] would make bringing a disparate impact case more difficult."

In short, the bill aims to strip HUD’s already weak power in dealing with residential segregation patterns.

Why housing advocates believe the Fair Housing Act was impotent to start with

The core reason fair housing laws exists is because this country's past is rife with discriminatory policies, like redlining, which systematically denied home loans to black families. That has had an outsize influence in shaping the racial geography of America — even today.

In fact, more black families live in poor neighborhoods now than 40 years ago.

And because housing discrimination often forced black families into ghettos, they weren't able to invest in housing in the same way as white families. That's partially why black families have struggled to accrue wealth:

So the Fair Housing Act was passed in 1968, one week after Martin Luther King Jr. was assassinated. The law says you can't refuse to let someone buy or rent a home based on race, color, religion, sex, familial status, or national origin. But the part under scrutiny, even from the early days of the law, was the portion that says communities receiving money from HUD must "affirmatively further" fair housing.

George Romney, Richard Nixon's housing secretary, used this law liberally. He withheld federal funds from predominantly white communities that perpetuated discriminatory housing practices. Nixon, however, quickly nixed this effort.

And thus began half a century of the federal government doing little in terms of actually "affirmatively furthering" fair housing.

In that period, HUD would ask communities to submit an "Analysis of Impediments" to fair housing, which is basically a form that explains why residents couldn’t find affordable housing and saying that they’re working on it. It was just moving around papers.

But this did little to actually affirmatively further fair housing. A ProPublica investigation found that since Romney’s time as housing chief, HUD has only withheld money two times from communities that violated the Fair Housing Act. That's a minuscule number, considering HUD has given money to 1,200 communities totaling $137 billion since 1974.

Why rolling back data is devastating for communities trying to plan for demographic shifts

The Obama administration solicited a large amount of feedback from communities receiving HUD funding, and eventually issued a new rule to give more teeth to the Fair Housing Act.

The rule asks localities to help them set their own fair housing goals — and then to help them reach these goals, HUD created data tools so they can better see these invisible factors that might discriminate against protected communities.

So in one sense, this tool takes away the feds’ ability to control local zoning. But it also takes the tool away from communities, which are trying to plan for an increasingly diverse population.

In fact, in the several years of conversations with communities receiving HUD money (summarized here), the feds found that local communities had a hard time seeing segregation patterns from a bird’s-eye view, so these data tools worked to makes these trends more visible.

These are the kinds of tools outside organizations would build to try to help housing advocates see various trends, including efforts to map “opportunity,” which shows which areas are in proximity to various resources. These data sets are often difficult for local communities to build themselves — and because of the economy of scale, it is much more efficient for HUD to build such a tool.

One could argue that you could build data-driven tools and avoid racial disparity data. But anyone who has dug into these data sets will find that the discriminatory history of this country is baked into our geography.