Elliot L. Richardson, 79, who shocked the nation and stunned the Republican Party in 1973 by resigning as U.S. attorney general when directed by President Richard M. Nixon to fire the special prosecutor investigating the Watergate break-in and subsequent coverup, died of a cerebral hemorrhage Dec. 31 at a hospital in Boston.

Mr. Richardson, a lifelong Republican, had served in the Nixon administration as secretary of health, education and welfare, secretary of defense and under secretary of state. During the presidency of Gerald Ford, he was ambassador to Britain and secretary of commerce. In the 1960s, he had been attorney general and lieutenant governor of Massachusetts. He also had served as U.S. attorney in Massachusetts.

But the defining moment of his career and the singular act for which he was best remembered was his decision to resign in October 1973 rather than comply with Nixon's order to fire Archibald Cox, the special prosecutor who was investigating the June 1972 break-in at the Democratic National Committee offices at the Watergate building in Washington. The break-in, and subsequent White House coverup, ultimately led to Nixon's resignation as president in August 1974.

In refusing to obey the presidential directive, Mr. Richardson helped precipitate a crisis of confidence in the government and increased the momentum of the unraveling Watergate scandal. He acquired a national reputation as a man of integrity who put principle ahead of partisan politics. But, in fact, he was deeply troubled by his decision to quit, friends said, because he felt he owed a debt of loyalty and allegiance to the president, who had appointed him to three Cabinet-level positions. He would characterize the episode in later years as "my brief period of notoriety."

Named U.S. attorney general in April 1973 to oversee the Watergate investigation and restore the public's shaken confidence in the Department of Justice, Mr. Richardson had been on the job only six months when on Saturday, Oct. 20, the White House ordered him to fire Cox, a former U.S. solicitor general and Harvard University law school professor whom Mr. Richardson had hired as Watergate special prosecutor.

This period already had been one of the most tempestuous in the history of the republic. The Watergate scandal was running at full throttle. Televised hearings on Capitol Hill that summer brought a stream of revelations of burglary, wiretaps, lies, duplicity and criminality at the highest levels of government.

In an unrelated matter, the vice president, Spiro T. Agnew, was under investigation in a criminal case. The U.S. attorney's office in Baltimore had uncovered evidence that while governor of Maryland, Agnew had taken bribes and kickbacks. As the nation's top law enforcement officer, Mr. Richardson also supervised that investigation, which ended in October 1973 with Agnew's resignation and a plea of no contest to a single count of income tax evasion.

The clash of wills that precipitated his resignation as attorney general followed disclosure during hearings at the Capitol that Nixon had routinely tape-recorded all conversations in the Oval Office at the White House. Special prosecutor Cox demanded access to the tapes. But the White House balked, and Nixon proposed a compromise. Sen. John Stennis (D-Miss.) would review the tapes and verify their content to the prosecutor's office. That was unacceptable to Cox. He wanted the tapes themselves, unedited and unabridged.

When Cox refused to yield, the White House ordered Mr. Richardson to fire him. Instead, the attorney general resigned, as did his deputy, William D. Ruckelshaus, when the White House directed Ruckelshaus to do the firing. Eventually, Cox was dismissed by Solicitor General Robert H. Bork.

Bork pulled the final trigger in the sequence of events that became known as the "Saturday Night Massacre." On Capitol Hill and in the media, the reaction was intense and extraordinary. Sen. Robert C. Byrd (D-W.Va.) spoke of it as a "brownshirt operation," evoking memories of the Nazi takeover in Germany. Editorial writers and columnists alluded to "an attempted coup d'etat."

On the Monday morning after he resigned, Mr. Richardson returned to the Justice Department, where his former employees greeted him with an enthusiastic and sustained ovation. "If I had any demagogic impulse," he told The Washington Post 19 years later, " . . . there was a crowd. . . . But I deliberately throttled back."

Circumspect and speaking with historical detachment, he told the men and women at the Justice Department that he had tried hard and sincerely to understand Nixon's position in refusing to yield the White House tapes. "I can only say that you have here a situation in which the president, and I know nothing to call this into question, believed that the confidentiality of communications to the president was fundamentally important," he said.

"The height of irony," Mr. Richardson would write in his 1996 memoirs, "Reflections of a Radical Moderate," ". . . was that even a belated display of openness could have saved Nixon from the consequences of his own evasion of it. . . . I said to Fred Buzhardt, counsel to the president, 'You ought, instead, tell Archie Cox to send over a truck and load it up with all the material he and his staff could possibly want.' In the event, if anything damaging was found, Nixon could issue a public apology and couple it with a convincing expression of penitence. The American people, I thought, would be more than likely to forgive and forget."

Upon learning of Mr. Richardson's death, President Clinton issued a statement recalling him as "an unparalleled public servant" and "a man of uncommon integrity, who put the nation's interests first even when the personal cost was very high."

Elliot Lee Richardson was born in Boston, a descendant of the earliest New England settlers and a relative of prominent Boston families. His great-grandfather, both grandfathers, his father, three uncles and two brothers all were physicians who served with distinction at Harvard University's medical school or Massachusetts General Hospital.

Breaking with the family tradition, the young Elliot Richardson decided to become a lawyer. "I was not sorry to pass up medicine as a career," he said much later. "It seemed too much like a book I had read before."

He followed his family tradition by graduating from Harvard, but his studies at Harvard's law school were interrupted by Army service in World War II. Serving in an infantry unit, he participated in the D-day landings in Normandy on June 6, 1944, and in subsequent combat operations in France. He received a Bronze Star and two Purple Hearts.

Returning to Harvard after the war, he received his law degree in 1947 after serving as editor and president of the Harvard Law Review. He was a law clerk for Judge Learned Hand of the 2nd U.S. Circuit Court of Appeals in New York, then in 1948 came to Washington as the law clerk for Supreme Court Justice Felix Frankfurter. So impressed was Frankfurter with Mr. Richardson's skills and abilities that in 1953, he proposed him for the presidency of Harvard, even though his former clerk was then only 33 years old.

In 1949, Mr. Richardson returned to Boston as an associate in the blue-chip law firm of Ropes, Gray, Best, Collidge and Rugg, remaining there for four years. During those years, he became convinced that the private practice of law "didn't match the satisfaction of doing a good job for the public."

For the rest of his professional life, he expended most of his time and energy in public office, returning to the private sector for only brief periods. He acquired a reputation as a super administrator with a limitless capacity for hard work and the political savvy to navigate the rocks and shoals of the most impenetrable bureaucracy.

Typically, he worked 12 to 14 hours a day at the office, where he was known as a notorious doodler who liked to wad up sheets of paper and shoot baskets with them. On weekends, he worked at home, often while simultaneously watching a football game on television or listening to a Beethoven sonata. He was a bird-watcher, and he swam, fished and played tennis and loved to putter in his yard.

Forbes magazine once described him as a man with a "first-class mind that does not make mistakes . . . a breathtaking grasp of complex detail, a penetrating analyst and problem solver."

Saul Pett, of the Associated Press, wrote that Mr. Richardson was "a man of immaculate attire and rare distinction, a flexible George Apley with wit . . . a relentless achiever with a dazzling variety of government experience, a man of elegance and charm with spectacular mental powers, a prince of the Eastern Establishment."

In 1953, Mr. Richardson joined the staff of Sen. Leverett Saltonstall (R-Mass.), but the next year, he returned to the Boston law firm, where he remained until 1957, when President Dwight D. Eisenhower appointed him assistant secretary for legislation in the Department of Health, Education and Welfare. His work in that period included the National Defense Education Act and developing Social Security legislation.

Returning to Boston in 1959 as U.S. attorney for Massachusetts, he gained a reputation as a hard-nosed prosecutor, and he was especially aggressive in tax fraud cases. More than three decades later, in "Reflections of a Radical Moderate," he wrote that "while I hate all forms of cheating, in my Inferno, tax evaders occupy a circle of their own. I see them not only as backsliders on their own civic responsibility but as stealing from their fellow citizens: The more successfully they escape what they owe, the more the rest of us have to pay. I take great satisfaction, therefore, in the fact that during my tenure as U.S. Attorney for the district of Massachusetts, every tax evader we prosecuted was convicted, and all of them went to jail."

Among the most widely publicized of those cases was the conviction of Bernard Goldfine, the textile manufacturer whose gifts to White House aide Sherman Adams had embarrassed the Eisenhower administration.

When John F. Kennedy became president in 1961, Mr. Richardson returned to the private practice of law in Boston. The next year, he lost the Republican primary for the Massachusetts attorney general's nomination, but in 1964, he was elected lieutenant governor of Massachusetts. In 1966, he was elected Massachusetts attorney general. He returned to Washington as undersecretary of state in 1969 when Nixon became president.

He served at the State Department until June 1970 when Nixon asked him to become secretary of the Department of Health, Education and Welfare, which by then had become an unwieldy and disorganized bureaucracy, beset with duplication of services, inefficient budgeting and a demoralized staff.

At HEW, Mr. Richardson tried to simplify procedures such as the processing of grants, consolidate duplicating programs and decentralize authority by giving greater responsibility to state and local governments. He came under liberal fire when the White House appeared to be undercutting busing programs for school desegregation. Remaining on the job, he described himself as "a man who measures his satisfactions by the scale of the possible. . . . Marginal pluses are always better than glaring negatives."

He was secretary of defense for only three months in 1973, but he was in the media spotlight in that period as the Nixon administration's spokesman on the legality of the Vietnam War tactic of bombing Cambodia.

After resigning as attorney general, he was a fellow of the Woodrow Wilson International Center for Scholars for two years, then in 1975 returned to government service as ambassador to Britain. In 1976 and 1977, he was President Ford's secretary of commerce, then until 1980, he was the president's representative to the Law of the Sea Conference in Washington.

From 1980 until 1992, he was a partner in the Washington office of the New York law firm of Milbank, Tweed, Hadley & McCloy.

Mr. Richardson, who lived in Mitchellville, was visiting relatives in Massachusetts at the time of his death.

His wife, Anne Francis Hazard Richardson, died July 26.

Survivors include three children, Nancy Carlson of Burlington, Vt., Henry Richardson of Washington and Michael Richardson of Montclair, N.J.; a brother; and seven grandchildren.

CAPTION: Richardson, center, is sworn in as secretary of defense. With him are President Nixon; Richardson's wife, Anne; and Chief Justice Warren E. Burger.