CHICAGO – When the Fair Housing Act was passed in 1968, it barred the outright racial discrimination that was then routine. It also required the government to go one step further: to actively dismantle segregation and foster integration in its place – a mandate that for decades has been largely forgotten, neglected and unenforced.

Last week, the Obama administration announced long-awaited rules designed to repair the law’s unfulfilled promise and promote the kind of racially integrated neighborhoods that have eluded deeply segregated cities such as Chicago and Baltimore. The new rules, a top demand of civil-rights groups, require cities and towns all over the country to scrutinize their housing patterns for racial bias and to publicly report, every three to five years, the results. Communities also have to set goals, which will be tracked over time, for how they will further reduce segregation.

“This is the most serious effort that HUD has ever undertaken to do that,” said Julián Castro, the secretary of housing and urban development, who announced the new rules in Chicago on Wednesday. “I believe that it’s historic.”

Officials insist they want to work with and not punish communities where segregation exists. But the new reports – based on a vast collection of geographic data that HUD will provide – will make it harder to conceal when communities consistently flout the law. And in the most flagrant cases, HUD holds out the possibility of withholding a portion of the billions of dollars it hands out each year.

The prospect of the new rules, which will cover housing patterns that exclude other groups, such as the disabled, has already spurred intense debate. Civil-rights groups pushed for even tougher rules but say HUD’s plans represent an important advancement on what’s been one of the most fraught frontiers of racial progress.

“Housing discrimination is the unfinished business of civil rights,” said Sherrilyn Ifill, president of the NAACP Legal Defense Fund. “It goes right to the heart of our divide from one another. It goes right to the heart of whether you believe that African-American people’s lives matter, that you respect them, that you believe they can be your neighbors, that you want them to play with your children.”

But conservatives have sounded alarms. Republicans in the House, worried about what they see as federal intrusion into local planning, have already tried to defund implementation of the rules. Conservative pundits say they represent an experiment in “social engineering” in which the government will force white suburbs to change their racial makeup.

“Let local communities do what’s best in their communities, and I would predict we’d end up with a freer and fairer society in 20 years than we have today,” said Rick Manning, the president of Americans for Limited Government. “Far freer and fairer than anything that would be dictated from Washington.”

The administration’s announcement comes less than two weeks after the Supreme Court reaffirmed the power of the Fair Housing Act to ban housing policies that harm minorities. After a years-long delay, it also arrives during a rare civil-rights moment, as the nation returns to familiar questions about the underlying causes of racial unrest in American cities.

“There is no question in my mind that part of the issue with Baltimore or Ferguson is about the relationship between the community and the police – but it’s much deeper than that,” Castro said. “It’s also fundamentally about people having opportunity in their lives. And where you live, in many ways, dictates the level of opportunity that you have.”

The Rev. Martin Luther King Jr. chose Chicago when, in 1966, he launched a campaign for “open housing” in Northern cities where blacks had been restricted to slums. On Chicago’s South Side, their neighborhoods had been “redlined” by banks that refused to lend to black homebuyers. Restrictive covenants in areas outside the ghetto barred blacks from moving in.

Real estate agents buttressed these patterns. The city’s housing authority concentrated public housing projects within these same neighborhoods. And the Federal Housing Administration, which heavily subsidized the migration of whites to the suburbs, historically blocked blacks from living there, too.

“The most profound form of social engineering was the creation and maintenance of segregated suburbs,” said Craig Gurian, a civil rights lawyer and the executive director of the Anti-Discrimination Center. “That is social engineering.”

Opposing views of HUD’s new rules are fundamentally about different interpretations of this history. Critics argue that the kind of overt discrimination that existed in 1968 is rare today.

“Fifty years ago, that was really a great argument,” Manning said. “Thirty years ago, it might have been somewhat substantive. But 1968 was a long time ago.”

Civil rights groups counter that past discrimination lives on in housing patterns that America has never addressed. They say their efforts are about removing the constraints on the housing market – such as zoning laws that bar apartment construction in suburbs and formulas that ensure affordable housing is built primarily in poor neighborhoods – so that lower-income and minority families will have more options.

In Chicago and many other cities, the racial lines drawn by history are largely the same ones that exist today. Black-white segregation in metropolitan Chicago, Detroit, Milwaukee and New York has eased only modestly in 40 years. In Chicago, white flight has meant that many once-white neighborhoods are now predominantly black. But over half a century, starting in 1960, Harvard sociologist Robert J. Sampson has identified just one neighborhood in the city that transitioned in the other direction.

These patterns have persisted in spite of the Fair Housing Act in large part because of the failure of the law’s “affirmatively furthering” mandate to actively promote integration. “You don’t undo” all this history, said Ifill of the NAACP Legal Fund, “just by stopping people from engaging in discrimination.”

George Romney, Mitt Romney’s father and the HUD secretary from 1969 to 1973, tried to withhold HUD funding from communities that fought desegregation. His efforts, swiftly blocked by the Nixon administration, are remembered today by civil-rights advocates as the fleeting moment when the federal government was most committed to integration.

HUD has never aggressively enforced the “affirmatively furthering” language, although it has pursued some complaints against communities for defying that part of the law. Westchester County, New York, for instance, has been mired for years in a legal battle with HUD, over a lawsuit claiming that the county misled the government by accepting funding without “affirmatively furthering” fair housing.

The county agreed in a 2009 settlement to build 750 affordable-housing units, primarily in communities with few minorities. The settlement also required the county to adopt a law banning landlords from discriminating against subsidized tenants. As some of those benchmarks went unmet, HUD began to withhold money from Westchester. The county has since decided not to pursue any more block-grant funds, an option that critics of the new rules warn many communities will choose.

“It’s not worth it because of the threat of lawsuits, the strings attached and the control that Washington can then exert over you,” said Westchester County Executive Rob Astorino. “You get involved with the federal government, and you can’t get out of bed with them.”

Here in Chicago on a recent morning, 17 women sat in a classroom learning how to wield their housing vouchers to bring up their babies in better neighborhoods.

The nonprofit Housing Choice Partners of Illinois handed out two maps on thick paper stock that the women could carry across town as they searched for new homes. One illustrated, in green, the “opportunity areas” in the city. The other showed Chicago color-coded by crime.

“The darker the orange, the higher the crime. We’re keeping it really simple,” said Shinnette Johnson, an education coordinator leading a recent orientation.

Most of the women lived in the dark-orange areas on the south and west sides, where high crime is accompanied by poor schools, deep poverty and racial segregation.

“If you look at State Street, there’s nothing on the State Street corridor for you to grow and prosper,” Johnson said, describing a stretch of Chicago’s historic Black Belt on the South Side. “It’s not even a store from 22nd to 55th.”

“Nope!” several women replied in chorus.

“There’s one store! On 55th at State. And what is it?”

“A liquor store,” one voice offered.

“A liquor store! That’s not a place I want to send my kids. And all the way down to 22nd, what’s there?”

A mother in the second row shook her head. “There’s no grocery stores. There’s no clothing stores. There’s nothing.”

Chicago for decades has remained one of the most segregated metropolitan areas in the country — black separated from white, poor isolated from wealthy, families who need housing aid living far from the schools they would choose for their children.

The seven-county metropolitan area recently produced a 133-page assessment as part of another HUD grant program that helped serve as a model for the new rules. Many local municipalities initially said they had achieved housing equality. The final report, though, bluntly concluded that concentrations of race and poverty in the region had remained “largely unchanged” for decades. And it included two stark population maps, showing the racial makeup of the region in 1980 and again in 2010.

“If you show those two maps next to each other, you can’t possibly look at that and say that we’re getting better, that we’ve solved this problem or that this is no longer an issue in the metropolitan area,” said Bob Dean, the deputy executive director for local planning with the Chicago Metropolitan Agency for Planning, which worked on the report.

In this context, it’s likely that only a third of the women in the orientation class will move to new homes in one of the opportunity areas. In a good year, that’s the organization’s success rate. “There are so many barriers,” said executive director Christine Klepper. “Sometimes I wonder how we get any moves.”

The units are too expensive. Or voucher-holders have to compete with market-rate tenants who don’t entail the same paperwork load. Or landlords reject them because of their vouchers, even though that’s illegal in Chicago.

Or, more often, there just isn’t much affordable housing in good neighborhoods, because the nicest places to live, whether in the city or the suburbs, are often the most effective at keeping out new development.

“If you think about it, we’ve only had a fair-housing law for 50 years,” Klepper said. “And we’ve had 300 years of slavery, Jim Crow, incarcerating black men, discrimination. To me, it’s not surprising that things have not changed much over time. It’s because we really haven’t tried.”

Many Americans support letting homeowners discriminate

WASHINGTON – When the Fair Housing Act first came into effect in the late 1960s and early 1970s, a substantial share of white Americans supported the kind of discrimination the landmark law made illegal. They believed that whites had a right to keep blacks out of their neighborhoods. They said in surveys that they’d prefer a housing law that protected a homeowner’s right to discriminate.

While that era sounds long ago, these positions took many years to shift. And that slow trajectory helps explain why there has long been little political will for the kind of desegregation – originally envisioned by the law – that the Obama administration now says it wants to enforce.

Since 1973, the General Social Survey has continuously asked whites which housing law they would vote for if they had two options: one saying a homeowner “can decide for himself whom to sell his house to, even if he prefers not to sell it to blacks,” and another saying a homeowner “cannot refuse to sell to someone because of their race or color.”

The second choice has been the law in America since the passage of the Fair Housing Act in 1968. But until the late 1980s, a majority of whites chose the first option.

The reversal over the last four decades has been striking. But as recently as 2014, 28 percent of whites still said they’d choose the law allowing homeowners to refuse to sell their homes to blacks.

On another General Social Survey question, a third of whites in 1972 agreed with the statement: “White people have a right to keep blacks out of their neighborhoods if they want to, and blacks should respect that.”

When the survey stopped asking the question in 1996, 12 percent agreed.

More recently, since just 1990, the share of whites who say they’re opposed to living in a neighborhood where half their neighbors are black has fallen significantly, too.

Notably, the share of whites who favor living in such a neighborhood has remained relatively stable for the last 20 years.

Alexander Polikoff, a long-time civil rights lawyer in Chicago, made this observation to me that may help explain that last picture: “It’s not that people in the large harbor racial animus, although there are some who do,” he says. “It’s that people are fearful of inundation.”