Twenty years ago, when the Rev. Martin Luther King Jr. led 200,000 blacks in their historic march to the Lincoln Memorial, the Jackson Clarion-Ledger summed up the story the next day in a typical front-page headline: "Washington Is Clean Again With Negro Trash Removed."

The Clarion-Ledger was perhaps the most racist major newspaper in the country. Over the years, its front page directed Mississippi readers to public lynchings and its columnists joked in print that scientists had found the cause of sickle-cell anemia--licking food stamps.

Last week, the newspaper's Tuesday morning headline blared markedly different news: "Clarion-Ledger Wins Pulitzer Prize." The ironies were immense. The Mississippi newspaper that had become synonymous with Deep South racism had been awarded journalism's top honor for meritorious public service in its coverage and editorial support of Mississippi's first major improvement of its public schools since desegregation and white flight left the system almost wholly black.

The turnabout was one of the most dramatic in the annals of American journalism. In the cluttered newsroom of the Clarion-Ledger, it should have been a moment of great triumph, and in many ways it was, with champagne corks popping and tears cascading down young reporters' cheeks.

But in classic, almost Faulknerian southern fashion, there was almost as much poignancy as triumph. Many of the tears were flowing for a man who wasn't there, the enigmatic and charismatic young heir apparent who had battled history, tradition and his own family to change the newspaper's course.

The story of the Clarion-Ledger's Pulitzer Prize is the story of Rea Hederman, the scion of a family whose tentacles reached out from Jackson's two newspapers into landlording, racist politics and virtual control of a state that still relishes the rebel yell.

To understand the Clarion-Ledger story is to understand the Hederman family story, a tale that begins early in the century when two hard-working, teetotaling brothers arrived here in a wagon from rural Mississippi, bringing neither money nor connections.

The first Hedermans, R.M. and T.M., went to work as printers and, through grit and tight-fisted living, saved enough money to buy the Clarion-Ledger in 1920, imprinting their stern, Baptist, segregationist views on it.

By the 1950s and '60s, when national attention was beginning to focus on race problems in the South, the sons of the original owners had expanded the empire to include the town's second newspaper, partial ownership of a television station, banking interests, land holdings and control of the Baptist church.

"They were Bible-quotin', Bible-totin' racists," said Bill Minor, a longtime Hederman antagonist whose own weekly newspaper eventually was overwhelmed by competition from the Hederman papers. "They were dictators who wanted to run the whole state--and they did it."

Across the street from the state capitol, the First Baptist Church became known as Jackson's Tammany Hall. Out of the pews of the church the Hedermans anointed governors like Ross Barnett, whose segregationist politics inflamed race riots at the University of Mississippi in the early 1960s. Barnett, in turn, appointed five Hedermans to state boards.

As late as the early 1970s, the race-baiting was almost as strong as it had been in the '50s. So was the monopoly control of news in Jackson.

"There wasn't a story . . . that couldn't be blocked by talking to one Hederman," Minor said.

In 1973, Rea Hederman, then 28 but already silver-haired, came home to change all that. He began recruiting bright, young reporters from around the country--most of them just out of college and most of them from the north.

"Rea's outside agitators," many of the locals called them, as did most of the seven other Hedermans who sat on the board of the 60,000-circulation Clarion-Ledger. The family was so close-knit that rather than bring the disputes out in the open, the Hedermans, while opposing him, let young Rea have his way.

Over the next years, Hederman expanded the editorial staff from 16 to 125. And, if much of Jackson was calling the Clarion-Ledger their "foreign newspaper," Hederman's brash young reporters romped into flashy expose after flashy expose.

"Nobody had done an investigative story in Mississippi in almost a century," said Bob Zeller, who stayed four years and now works at the Long Beach, Calif., Press-Telegram. "It was like walking every day into an apple orchard where no one had ever picked an apple."

Hederman's young turks wrote about police brutality toward blacks in Jackson and chronicled the plight of poverty-stricken and hungry black farmers in the Mississippi Delta. They began winning national journalism awards: the George Polk Award, the Heywood Broun Award and then, in 1979, the Robert F. Kennedy Award for defending the underprivileged.

For Rea Hederman, however, it was like walking every day into a mine field.

In board meetings he faced his family, whose politics remained as rigid as ever. When the paper won the prestigious Kennedy award, half the family wanted him to reject the prize. Instead, he took 11 staff members to Hickory Hill to accept it from Kennedy's widow, Ethel, and brother, Sen. Edward M. Kennedy (D-Mass.).

Outside the board room, Hederman met suspicious stares from some of his recruits. Whenever he shook his head on a story idea, some of his own northern rebels thought he had caved in to the family.

To many of Hederman's imports--over eight years, he hired more than 300--the changes came too slowly and they blamed the man who wooed them to Jackson. Some left bitterly, a decade being a wisp in the wind in the Deep South, an eternity to a young reporter on the move.

Not long after the Kennedy award, which only a Pulitzer could top in Rea Hederman's reach to bring his newspaper into the 20th Century, the wear began to show. His marriage broke up. He fell in love with one of the photographers he had brought in from the University of Missouri.

"You have to understand the family," said Minor, a man who admired no Hederman, not even Rea, but nevertheless appreciated the southern Gothic nature of the Hederman story. "It took a small miracle for them to choke down the Kennedys. No miracle would let them choke down a divorce and scandal."

After seven years of 16-hour days, Rea Hederman began showing up in the office less and less often.

"I started seeing him twice a week, then once a week, then every couple of weeks," said Robert H. Gordon, whom Hederman had hired as managing editor. "Then one day he came in and told me, 'I've lost a lot of blood downstairs in the board room . Now it's your turn.' " Gordon didn't take him seriously. "He flashed his smile at me and added, 'See you in a couple of weeks.' "

That was early 1982, which would become the Pulitzer year. No one at the Clarion-Ledger has seen him or heard from him since. The divorce went through, his remarriage two months later. The staff heard he was living in New York. They heard reports of random spottings in Jackson. They began calling him Howard Hughes Hederman.

Behind the board room doors, the rest of the tightly knit family was beginning to unravel.

Six months later, with the Pulitzer project only partly finished, the newsroom got its next shock. The Hedermans announced they were selling the Clarion-Ledger and its sister paper, the Jackson Daily News, to Gannett, a newspaper chain.

"We were terrified," said Nancy Weaver, 29, an investigative reporter who had first discussed the prize-winning project with Hederman. "We talked about rushing it into print before the Gannett people got here."

But they waited--and were surprised. Gannett and the Clarion-Ledger's new editor, Charles Overby, backed them to the hilt. Overby held the series till the eve of a special legislative session on the education reforms in December, then deluged the reluctant legislators with 51 stories and 27 editorials in 24 days.

The reforms passed. The Pulitzer came a week ago, more Gannett's prize than Rea Hederman's by this time, although Overby gave Hederman half the credit.

Hederman did not call his old newsroom the day the Pulitzer was awarded. But he broke his year of public silence in an interview in Washington late last week, adding more ironies to the story of the Hederman family and the newspaper.

In his early 20s, he said, journalism and especially his family's newspapers carried no allure for him. His early goal was Wall Street. But everywhere he went, he said, "the haunt" followed him.

"I began to feel that no matter where I went I would always be embarrassed," Hederman said. So he went home to do something about the racist papers he had left in the South.

Now, a decade later, a different haunt follows him. He doesn't call the young reporters he hired because he feels guilty "about abandoning them." He returns to Jackson only to see his children because he says he feels guilty about tearing his family asunder.

The Hedermans now are selling everything to avoid dealing with each other, he said. His father, Robert, and one or two others have stuck by him, he said. But as for the others, "it's an irrevocable split." He said he doubts that anyone outside the family "will ever understand what went on inside the family."

"It hurts," he said of the dream he never wanted but now feels he has lost. "It hurts a lot."

But in Jackson, there are two newspapers that no longer print race-baiting headlines. And scattered around the country are several hundred Hederman alumni, many working on major newspapers, who came of age with the Clarion-Ledger.

Johanna Neuman, a Berkeley graduate who now is a national reporter in Gannett's Washington bureau, was hired by Hederman in 1976. She vividly recalls driving across the Mississippi border with California license plates, feeling like an "outside agitator" and nervously looking over her shoulder to see who was following her.

Neuman said Hederman changed not only the Clarion-Ledger but also the young reporters who went there, too.

"We came to Jackson as children," she said, "but left there as adults."