Housing discrimination may soon get a boost. A new executive order from the Trump administration strikes at civil rights protections safeguarding some of our most vulnerable neighbors: communities with long histories of harm at the hands of federal policies.

Late last month, the White House banned federal agencies from using disparate impact analysis, a legal doctrine essential for rooting out bias and repairing damage from decades of discrimination. For years, Americans have pointed to disparate impact to challenge restrictive zoning laws, call out unfair tenant screening tools and desegregate neighborhoods.

The concept is simple but powerful. Disparate impact analysis aims to protect people from the harm of policies that appear neutral but nevertheless have a discriminatory effect.

Let’s say an employer requires job applicants to meet criteria that have nothing to do with job performance, while clearly disadvantaging a particular group. That was the scenario in a case decided by the U.S. Supreme Court in 1971. Policies like this, America’s highest court ruled, are prohibited by the 1964 Civil Rights Act.

Read more: Trump’s HUD Cuts Are Gutting Protections Against Housing Discrimination

The tenets of employment law, especially around equal opportunity, are often cited in housing cases. And the Supreme Court’s first disparate impact decision strengthened generations of federal regulations and state laws advancing housing justice.

But the court made the connection explicit in 2015 when it used disparate impact analysis to explain its decision in a housing dispute. The offense there, the Court wrote, violated another landmark civil rights law: the 1968 Fair Housing Act.

Fair housing attorneys like us rely on disparate impact analysis because the nature of bias has changed. It’s less common today (though not unheard of) for housing transactions to involve blatant discrimination.

Instead, bias hides behind handshakes and smiles, with unfair denials often blamed on algorithms or the nation’s severe housing shortage.

U.S. law prohibits this gaslighting. Writing for the majority in the 2015 case, Justice Anthony Kennedy concluded: “The Court acknowledges the Fair Housing Act’s continuing role in moving the Nation toward a more integrated society.” Disparate impact analysis, the Supreme Court has repeatedly made clear, is essential to fulfilling the letter and spirit of civil rights law.

But the White House rejects this fact. With an Orwellian touch — and frankly, disrespect — its April 23 executive order claims to “restore the true promise of the Civil Rights Movement” and “ensure equal treatment under the law.”

That couldn’t be farther from the truth. Again and again, we’ve seen the power of disparate impact analysis when defending neighbors unfairly blocked from housing access.

Six years ago, our organization reached a settlement with a property manager that had set up a blanket ban on renting to people with criminal convictions. We argued this practice had an outsized impact on Black applicants, who are unfairly overrepresented in the criminal legal system. Our settlement forced the management firm to develop a new policy — soon rolled out to its affiliated properties nationwide — to first screen applicants on income and credit and then conduct a limited and relevant criminal background check.

Disparate impact advocacy continues here and across the country. Recently we sued a corporate property manager our investigators found telling recipients of Housing Choice Vouchers that no units were available. This was a violation of Virginia law, as our state prohibits discrimination over the source of income used to pay rent. But federal disparate impact protections also come into play.

The 1968 Fair Housing Act prohibits discrimination rooted in race, gender and family status. And since voucher holders are most likely to be Black women with children, refusing rentals to those with vouchers has a disparate impact on this group. It’s bias — and it’s unlawful.

Working with advocates around the country, we’ve seen disparate impact not only in tenant screening policies around criminal records and bans on renting to voucher holders. All too often, localities use zoning to sharply limit apartment construction, disproportionately harming Black and Brown communities. We’ve even found requirements to document citizenship status when signing up for public utilities. These hurdles leave vulnerable Americans at risk of losing access to housing, despite laws that should protect them.

The Trump administration’s attack on hard-won civil rights protections will not go down without a fight. And there’s much we can do.

• Executive orders don’t change the law. Advocates everywhere can keep litigating on disparate impact analysis, because the law is clear and unchanged.

• Make new laws that affirm fairness. Let’s call on our state and local representatives to make disparate impact protections like those on the books in California, Colorado, Illinois, Minnesota, and New York. Bans against source of income discrimination, enforced in Virginia and dozens of other states and localities, represent another supportive way forward.

• Fund fair housing organizations. As the U.S Department of Housing and Urban Development all but obliterates its Fair Housing and Equal Opportunity division, fair housing nonprofits — agencies like ours that handle 75% of housing bias reports — need support to enforce civil rights law. Your state, possibly even your city or county, has at least one of these organizations. They need you.

It’s easy to get lost in the executive order storm — to think that a new regime, governing by fiat, has upended civil rights law. But we can and must fight back. Generations of systemic harm can be addressed by disparate impact advocacy. And our neighbors are counting on us.

This post was originally published on Next City.