When Congress passed the national Fair Housing Act 10 years ago this month, President Johnson said that with the law "we shall strike for all times the shackles of an old injustice."

Today some of the shackles have been smashed, and many neighborhoods that were closed to blacks a decade ago are now integrated.

But in most places across America blacks still live next to blacks and whites still live next to whites. Although figures are not available, one demographic expert, Karl E. Taeuber of the University of Wisconsin, says the country "is probably somewhat more integrated now but not substantially so."

The reasons are being explored in Washington this week at a conference sponsored by the Department of Housing and Urban Development and the National Committee Against Discrimination in Housing, a nonprofit civil rights group.

Perhaps the conference should be held here instead.

Nowhere is it easier to see why the nation has failed to realize the equal housing dream of the 1968 law than in this big blustery city, which is said to be the most segregated in the country.

Take Bridgeport, the working class neighborhood of Chicago's last four neighborhood of Chicago's last four mayors, including the late Richard J. Daley and his successor, Michael A. Bilandic.

Bilandic has denied that Bridgeport is racist, but Sidney Feldman, who published the weekly Bridgeport News, acknowledges that the community actively works to keep blacks out. Of its 78,000 people, many of whom work at city hall, "only half of 1 per cent are black," he said.

"I've preached it myself: if you don't leave your home, no one can move into it," Feldman continued. "When they tried to move in, our people tried to make them feel unwanted or caused trouble for them."

Feldman was interviewed in his red storefront office on S. Halsted Street amid pictures of his 12 grandchildren and drawings of Daley and Bilandic. He noted proudly that Bridgeport was the center of the 11th Ward, the political base from which Daley "became such a power that he almost controlled the United States."

Asked who in the community has caused trouble for blacks, the publisher replied, "The whole community would do it."

Two incidents last summer illustrate his point.

In one case, described by Legal Assistance Foundation attorney William P. Wilen, a white woman in a rented bungalow allowed her visiting grandson, who is a dark-skinned Hispanic, to play in her yard.

Next day the landlord, who apprently had been called by neighbors, came to the woman's door and asked, "Who's the nigger-kid?"

Later the neighbors became upset when two blacks helped relatives of the woman move into a flat behind her house. People gathered, shouting racial epithets, and police were called to disperse them. Next day the landlord canceled an agreement to let the woman buy the bungalow she was renting.

The woman won an out-of-court settlement of $750 plus three months of free rent. "She moved elsewhere," said Wilen, "because her daughter's car window had been broken, a foster child had been beaten up, and she was being verbally abused by the neighbors, who called her a 'nigger lover.' For years she had been a precinct captain in the 11th Ward."

The other incident involved a white couple - a printer and his wife - who said that when they invited a black couple to their Bridgeport apartment, their landlord told them "colored people" didn't belong there and warned that if they did not make their guests leave, they would have to move.

"He also told us the guys at the corner tavern were going to come and bust in all the windows," the wife said. When the downtown press wrote about the couple, the landlord denied threatening to evict them.

"He never actually asked us to move afterward," the wife said, "but we moved anyway. We were going to have a baby and needed more room. And we got a lot of hate mail."

Publisher Feldman said his paper did not carry the story "because it doesn't interest me." But he added, "The landlord was afraid people would think he had rented to blacks and they would come and burn his building down. This is an underhanded war."

Feldman said Bridgeport residents - who are mainly of Polish, Lithuanian, Irish, Italian and German descent - are not prejudiced against blacks.

"It isn't the color; it's all the things that come afterward," he said. "With them comes destruction, different mores, a different set of morals, use of dope, crime, and there are so many blacks on relief."

As he prepared to leave his office for the day, Feldman pointed to the rainy street of small shops and said sadly, "I look around and I know it's going to happen. The law says anyone can live where they want. But if you know your area has a chance of being a shambles, are you going to let them in?"

Kale Williams, who has been active in the fair housing movement since the early 1960s, maintains that the 1968 law has been vitiated by real estate marketing practices.

Williams, who is staff director of the leadership Council for Metropolitan Open Communities, said that many home seekers - both white and black - do not know what housing is available to them. This is reinforced by newspaper advertising practices.

"Here the Sun-Times does not distribute its Friday Homelife section, which has many suburban home ads, to the South Side, where most blacks and Latinos live.

"So at every step along the way, the weight of the system is to channel black home seekers back into black areas or to the edge of white areas."

Williams noted that certain parts of Chicago - including the Lake Front on the North Side and Hyde Park-Kenwood and Beverly on the South Side - and certain suburbs are integrated. But there are still places, including Berwyn and Cicero, "that are highly resistant to blacks and use harassment to keep them out," he said.

(Blacks are estimated to make up about 45 percent of Chicago's 3 million population and about 20 percent of the metropolitan area's 7 million people.)

Williams charged that parts of Chicago underwent "rapid racial transition - complete change from white to black in short periods - with the active manipulation of the real estate industry." The manipulation included steering blacks to certain areas and panic peddling, or scaring whites into selling out, he said.

Thomas C. Hughes, executive vice president of the Chicago Real Estate Board, denied that the industry was making any organized effort to steer blacks or panic whites.

Most panic peddling was practiced by speculators, not by licensed brokers, and was "eliminated long, long before the passage of the 1968 law," he said. "Steering is not prevalent now either."

Hughes said most of the real estate agents indicted seven years ago on charges of manipulating Federal Housing Administration loans "were not associated with our board." The FHA-insured loans allowed many poor blacks to buy houses they could not afford and later abandoned. Asked if the board had ever taken any action against a member, he replied, "Quite frankly, no, not in civil rights problems.

The board has, however, signed an affirmative marketing agreement with HUD committing it to take extra steps to insure equal service to all buyers, sellers and renters. More than 400 of 1,724 boards belonging to the National Association of Realtors have signed such agreements.

Gale Cincotta's neighborhood of Austin on the Far West Side of Chicago is a classic example of a community devastated by the system that Williams described.

Cincotta, who headed her neighborhood organization in ther late 1960s and who now directs a coalition of such groups called National People's Action, said the other day that in 1969 the number of real estate agents in Austin jumped from 35 to 300.

"In the early '70s we saw whole blocks change from white to black in six months. Real estate people would come door to door and tell us our homes were losing value and would show us pictures of blacks on leaflets that said, 'Meet your new neighbors.'

"The board of education didn't plan for the influx of new kids, and my son's elementary school went from 975 to 4,000 students between 1968 and 1971.

"The beauty shop moved and the cleaners moved and the savings and loan a block away from me moved, and we got a lot liquor stores and fast-food, fried chicken places. We lost all our doctors but six.

"We couldn't get loans to fix our houses, and the city cut services - garbage was collected only once a week."

Instead of moving, Cincotta stayed and fought. She organized school boycotts that finally forced the city to spend $30 million on new schools. Services were restored. Soul patrols were organized to combat street crime, and local citizens, led by Cincotta, held marches in a campaign to drive prostitutes out of Austin. "We did - for a while," she laughed.

In 1972 she helped organize a national housing conference in Chicago that is credicted with securing passage of the 1975 Home Mortgage Disclosure Act, requiring lending institutions to tell where they make home loans.

Austin's 126,000 residents still have their problems. Large dilapidated apartments are being abandoned and some city services are again being withheld, its citizen complain.

Cincotta notes, however, that the community, now largely black, "is still a good one. We have three hospitals, a park with tennis, golf and a pool, and we have good people. But we need someone - the city or the feds - to help us."

To Kale Williams, a major problem in keping integrated neighborhoods stable is whites' fear of economic decline after blacks move in.

"It's very hard to convince people it doesn't have to be that way," he said.

Two communities that are trying are Chicago Lawn, the Southwest Side area where Nazis have clashed with civil rights demonstators in Marquette Park, and the village of Oak Park, a suburb adjacent to Austin.

In Chicago Lawn, the Nazis have been forced to take down the huge "Stop the Niggers" banner from their building on 71st Street, but on mailboxes and lightpoles throughout the area are small signs with swastikas, skull and crossbones and the words, "Niggers Beware."

"The Nazis are only a small group, but they play on the fears of the large Lithuanian population here," said James Capraro, executive director of the Greater Southwest Development Corp.

The development corporation, supported by leading businesses in the area, has attracted $3 million worth of renovation and investment on the four blocks intersecting at 63rd and Western Avenue. It is spending nearly $1 million to rehabilitate houses in a 3-by-12 block area between Chicago Lawn and the all-blacks, crime-ridden and badly deteriorated West Englewood area.

Capraro has designed a slide show of scenes from three neighborhoods. One is devasted, the second is neat and middle class, and the third is upper class. Then he asks his audiences to guess who lives in each.

"All are black neighborhoods in the Chicago area," he says when they guess wrong.

Upper-middle Oak Park, which was the home of architect Frank Lloyd Wright and novelist Ernest Hemmingway, watched in dismay as nextdoor Austin declined economically. In 1972 the village started a counselling service aimed at dispersing throughout the community's rental units the blacks who are moving in at a rate of 15 to 20 percent a year. Now 6 to 8 percent black, the village also has recently begun an advertising campaign aimed at attracting whites who want to live in an intergrated community.

Bobbie Raymond, who heads the Oak Park Housing Center counselling service, said the village's efforts have been attacked by blacks and whites. "But integration has never been maintained by letting things go normally," she insisted. "You have to fight and you have to spend money and you have to interrupt the natural processes. You have to say, 'What can we do to help intergration?'"

Changing attitudes lead some demographers to think that residential segregation will diminish over the next decade. For instance, in the Detroit area the proportion of whites saying they would not be disturbed if a black moved into their block increased from 40 to 79 percent between 1958 and 1976, says Reynolds Farley, associate director of the Population Study center at the University of Michigan.

But in another 1976 study of the area, which he calls "Chocolate City, Vanilla Suburbs," Farley found that while blacks like intergrated neighborhoods, they are reluctant to be the first black family on the block. And whites are reluctant to remain in neighborhoods where blacks are entering in significant numbers, he said.

Even with minimum integration - one black and 14 white families - Farley found that nearly a quarter of the whites said they would be uncomfortable. While only 7 percent said d they would try to move out, 27 percent said they would not move into such a neighborhood.

When the black proportion reached one third, more than half the whites interviewed said they would be uncomfortable, 41 percent said they would try to move out, and nearly three quarters said they would not move in.

"We anticipated we'd find young, well educated whites and blacks that had a liberal attitude on housing integration, and we didn't find them," Farley said in an interview.

"That's why we don't hold much hope for integration, at least in the Detroit area, in the near future," he said. "And unless attitudes are different elsewhere, the process that produces a chocolate city with vanilla suburbs will be repeated around the country."