WASHINGTON -- The agonies and ecstasies of Richard Milhous Nixon, the 37th president of the United States, and the endless controversy over him, colored American life and politics for nearly half a century, from his election to the House of Representatives in 1946 to his death yesterday at the age of 81.

From the peaks of his election to the presidency in 1968 and re-election in 1972, to the depth of his resignation in disgrace in 1974 when faced with impeachment over his cover-up of the Watergate scandal, Mr. Nixon rode a political roller-coaster that might have broken a less determined man.

In his 48 years of public life, he demonstrated a remarkable ability to absorb major setbacks and resurrect his political fortunes. His election to the White House came after a narrow defeat for the presidency in 1960 at the hands of John F. Kennedy and a failed effort two years later to win the governorship of California.

Even after he was forced from office in 1974, he managed through his writings and occasional public utterances over the nearly 20 years remaining in his life to re-establish his voice as an authority in foreign affairs, first constructed as a widely traveled vice president under President Dwight D. Eisenhower from 1953 to 1961.

That reputation later was cemented when, as president, he opened diplomatic relations with the Communist regime in China that he had so vigorously opposed in a long career as a self-styled anti-Communist. In all, he wrote nine books on politics and foreign policy, eight of them after his resignation. On the day that he suffered the stroke that would lead to his death, the page proofs for his latest book, "Beyond Peace," were delivered to his office not far from his home in the northern New Jersey suburb of Park Ridge.

A sports enthusiast who equated the political life with sports, Mr. Nixon in a 1968 interview summed up the philosophy that drove him in these words: "Anybody in politics must have great competitive instinct. He must want to win. He must not like to lose, but everything else, he must have the ability to come back, to keep fighting more and more strongly when it seems that the odds are the greatest. That's the world of sports. That's the world of politics. I guess you could say that's life itself."

Mr. Nixon was known early and through most of his career as an intensely partisan political in-fighter. His win-at-all-costs intensity, conveyed to his associates, proved to be his undoing when agents of his re-election committee were caught breaking into the offices of the Democratic National Committee at the Watergate complex in Washington on the night of June 17, 1972.

Press investigations and congressional hearings uncovered a host of other abuses of presidential power, including the bribing of the Watergate burglars to keep quiet.

Although Mr. Nixon steadfastly insisted that he was not involved in any of it, proclaiming at one memorable point that "I am not a crook," the disclosure of tape recordings made of conversations he had had with associates in the Oval Office finally produced a "smoking gun" exchange in which it was clear that he was aware of the cover-up attempts and was part of them.

With a grand jury naming him an "unindicted conspirator" and a House committee approving three articles of impeachment against him, Mr. Nixon finally stepped aside on Aug. 9, 1974, still declining to acknowledge the degree of his complicity in the affair.

Although he later did say that he had allowed attitudes to flourish in his political inner circle that led to the excesses of Watergate, he went to his death without ever explicitly confessing to personal wrongdoing.

The controversy that surrounded Mr. Nixon through all of his political career reached another fever pitch a month later when his hand-picked vice president and successor, President Gerald Ford, suddenly pardoned him of all crimes committed or allegedly committed in the Watergate scandal.

The action brought a storm of protest down on Mr. Ford and was widely regarded as a major factor in his defeat for a full presidential term in his own right in 1976. The pardon, however, was essential to Mr. Nixon's ability to struggle out of the depression of his resignation and to rebuild his public image.

A young dreamer

From a storybook beginning in a tiny house in the small California town of Yorba Linda, where Mr. Nixon was born to economically struggling parents on Jan. 9, 1913, he dreamed of greater horizons beyond. In later life he often talked of lying in bed at night, listening to the whistle of a passing train and wondering where life's journey would take him.

He was a diligent student at Whittier College, from which he graduated in 1934. He graduated from Duke Law School with honors in 1937 and went back to the town of Whittier, Calif., where he met and married a local school teacher, Thelma Catherine "Pat" Ryan, in 1940, after a courtship that bloomed when they participated in amateur stage productions. Mrs. Nixon died last year. Their two daughters, Tricia and Julie, rushed to their father's bedside shortly after the stroke that hospitalized him Monday.

Young Mr. Nixon practiced law in Whittier for about five years before going to Washington a month after Pearl Harbor as a lawyer in the Office of Price Administration dealing with tire rationing. In August 1942, he joined the Navy as a lieutenant junior grade, was sent to the South Pacific, and rose to the rank of lieutenant commander in late 1945.

While renegotiating Navy contracts in a Baltimore office as he awaited his discharge, Mr. Nixon was contacted by a search committee of local Republicans on the recommendation of a former president of Whittier College.

They asked if he was interested in running for the House of Representatives against a 10-year incumbent Democrat, Jerry Voorhis. He returned to Whittier, where he won the committee's acceptance.

From the start, Mr. Nixon demonstrated a fierce, attacking style of campaigning in five debates and in newspaper advertisements that accused Mr. Voorhis of receiving support from a "Communist-dominated" labor political action committee. Though Mr. Voorhis denied the allegations, Mr. Nixon won with nearly 57 percent and was on his way up the political ladder.

Alger Hiss

In the House, he served on a committee on European recovery and on the Committee on Un-American Activities, which proved to be his ticket to higher political office. He was a tenacious interrogator and investigator in the 1948 case alleging that Alger Hiss, a high State Department aide, had passed official secrets to the Soviet Union.

A critical break in the case came when Whittaker Chambers, a former Communist witness, produced microfilm incriminating to Mr. Hiss out of a hollowed-out pumpkin on his farm near Westminster. Mr. Nixon used these "pumpkin papers" to build a case against Mr. Hiss, who was eventually convicted of perjury. Mr. Nixon basked in his new reputation as a tough Communist-hunter.

In 1950, a restless Congressman Nixon ran for the Senate against Democratic Congresswoman Helen Gahagan Douglas. In a bruising Democratic primary, Mrs. Douglas was accused by her opponent of voting consistently with Rep. Vito Marcantonio of New York, "an admitted friend of the Communist Party." Mr. Nixon picked up the refrain, and his literature referred to her as "the Pink Lady." Hundreds of thousands of handouts were printed on bright pink paper -- popularly known as "The Pink Sheet" -- purporting to show the "Douglas-Marcantonio Voting Record." Mr. Nixon won by a whopping 680,000 votes.

Eisenhower ticket

Only two years later, he was moving up the ladder again. Although the California Republican delegation including Mr. Nixon was committed to Gov. Earl Warren as its presidential favorite son, the young senator conducted discreet discussions

with Gov. Thomas E. Dewey of New York, the central figure in the bid to obtain the Republican presidential nomination for Gen. Dwight D. Eisenhower. Dewey encouraged Mr. Nixon to think of himself as a possible running mate.

As the California delegation sped to Chicago by train for the party's national convention, Mr. Nixon boarded in Denver. He circulated a poll he had taken indicating that Mr. Eisenhower was by far the popular choice and, some said later, urged delegates to abandon Mr. Warren in favor of the general, then trailing Sen. Robert A. Taft of Ohio in unofficial delegate counts. In the end, the delegation held for Mr. Warren, but by then Mr. Eisenhower didn't need it and was nominated.

Mr. Nixon's efforts, however, were not forgotten by Mr. Dewey and other Eisenhower insiders. They pressed his name on the general, who was so new to presidential politics that he was not aware that the choice of a running mate was his to make. He accepted Mr. Nixon as a young Westerner who would add balance and, his advisers hoped, California's electoral votes to the ticket.

In a one-sided fall campaign against Democratic Gov. Adlai Stevenson of Illinois, the only mild threat to Mr. Eisenhower's election -- but a critical one to Mr. Nixon's political future -- was a controversy over what came to be known as "the Nixon slush fund."

'Checkers speech'

The press reported that a group of California supporters had been contributing to a fund enabling Mr. Nixon to travel and make speeches, which the Democrats quickly attacked as a violation of the high ethical standards Mr. Eisenhower had pledged to bring to Washington.

Mr. Dewey, who had been Mr. Nixon's strongest booster for the vice-presidential nomination, argued that Mr. Nixon would have to be dropped from the ticket. The controversy triggered Mr. Nixon's famous "Checkers speech" in which he defended himself and listed his family's modest possessions, including a cocker spaniel puppy given to his daughters. Somberly, he vowed that "regardless of what they say about it, we're gonna keep it."

In a deft maneuver to take the decision out of Mr. Dewey's hands, Mr. Nixon appealed to the television viewers to tell the Republican National Committee whether he should leave the ticket. The response was overwhelmingly in his favor, and Mr. Eisenhower agreed to keep him as his running mate. They were elected in a landslide, and again in 1956.

As vice president, Mr. Nixon established his reputation as a foreign policy expert as a result of a host of good-will assignments abroad representing the president. And in 1959, he held a famous "kitchen debate" with Soviet Premier Nikita S. Khrushchev over the relative merits of their two countries' societies.

On three separate occasions in his vice presidency, Mr. Nixon seemed close to succeeding to the presidency when Mr. Eisenhower suffered a heart attack, a stroke and underwent surgery for an intestinal disorder. Mr. Eisenhower recovered each time, but the illnesses raised his concerns about presidential succession. He did not think Mr. Nixon to be of presidential caliber at that time, and in 1956 he considered dumping his vice president, suggesting to him that he might better prepare himself for the presidency by taking a Cabinet post. Mr. Nixon declined and stayed on the ticket.

As 1960 approached and Mr. Nixon was preparing to run for the Republican presidential nomination, Mr. Eisenhower was asked at a news conference to name "a major idea of his you had adopted" during Mr. Nixon's nearly eight years as vice president. The president replied: "If you give me a week, I might think of one. I don't remember."

Taking on Kennedy

Such embarrassments did not slow Mr. Nixon. He won the nomination after Gov. Nelson A. Rockefeller of New York, judging Mr. Nixon to be unstoppable, bowed out without a fight.

Mr. Nixon's defeat at the hands of Mr. Kennedy, in a campaign in which Mr. Nixon unwisely pledged to campaign in all 50 states and drove himself to the point of exhaustion, led most political observers to write him off as a political figure. That view was compounded by his 1962 defeat in the California governor's race, after which he told reporters "you won't have Nixon to kick around anymore."

But by dint of service to the party and refusal to be written off, he completed a remarkable comeback with his narrow presidential victory over the Democratic nominee, Hubert H. Humphrey, in 1968.

Mr. Nixon shook the "loser image" that had plagued him since 1962 by scoring a sweep of the Republican primaries starting in New Hampshire, where he was so strong that his lone challenger at the time, Gov. George Romney of Michigan, withdrew days before the voting.

Mr. Nixon was nominated on the first ballot and sprang a surprise of his own by choosing the little-known Gov. Spiro T. Agnew of Maryland as his running mate.

Mr. Agnew almost at once in the fall campaign established himself as the same sort of political hatchet man that Mr. Nixon himself had been accused of being in his congressional races and as Mr. Eisenhower's running mate.

The war in Vietnam became a major focus of that campaign, with Mr. Nixon indicating he had a plan to end it but declining to discuss it in any detail, in deference to peace negotiations then ,, going on. The Democratic opposition, already seriously split over Vietnam, and the news media were ineffective in pressing Mr. Nixon on the matter.

While Mr. Humphrey campaigned in his trademark dawn-to-midnight fashion, Mr. Nixon, in contrast to his own frenetic stumping in 1960, ran a tightly controlled and disciplined campaign that took pains to present him at his sharpest and most relaxed -- and with minimal exposure to the inquiring press corps. At the same time, he made deft use of television, avoiding the pitfalls of spontaneity and holding staged television "town meetings" with "average voters" who had been carefully selected by his aides.

Onto the White House

In spite of the deep divisions in Democratic ranks, Mr. Nixon managed only in that 1968 campaign to hold the strength he had in the polls at the start: about 43 percent of the popular vote. But it was just enough to edge Mr. Humphrey, 43.4 percent to 42.7, with 13.7 percent for independent candidate George C. Wallace, former governor of Alabama.

In his first statement after the results were certain, Mr. Nixon said the "character of the new administration" was symbolized in a campaign sign he said he saw being held by a teen-ager in Deshler, Ohio, that read: "Bring Us Together." And in his first inaugural address he pleaded for a cooling of the hot rhetoric that marked the Vietnam controversy and the racial unrest of the time.

But with Mr. Agnew in the forefront, the Nixon presidency soon got caught up in the bitterness over Vietnam, fired by a generation of young Americans disenchanted with establishment politics and alienated from society in general. Mr. Nixon sought at first to stay above the fray, using Mr. Agnew as his rhetorical battering ram, but in time he was out on the firing line himself, referring to anti-war student demonstrators at one point as "bums."

Vietnam heats up

In late April of 1970, Mr. Nixon ignited an even more intense uproar over Vietnam by sending U.S. troops into Cambodia in what he labeled an "incursion" only, to clear out North Vietnamese and Viet Cong sanctuaries there. But war critics charged that he was widening the war. More protests erupted on American college campuses, and on May 4 four students were killed at Kent State University in Ohio when National Guard troops fired on anti-war demonstrators.

Despite the poisonous climate, Mr. Nixon maintained considerable popularity as the economy at home, in the face of stubborn inflation, began to improve in 1972. He tried wage and price controls but finally abandoned them. He proposed ambitious welfare reforms but was stymied in this and most other domestic initiatives by the Democratic Congress. He did, however, create the Environmental Protection Agency and, under the banner of "The New Federalism," institute revenue sharing with the states.

His famed "opening to China," masterminded in conjunction with his national security adviser, Henry A. Kissinger, in 1971 and capped by a Nixon visit to Beijing in 1972, was hailed as one of the great American diplomatic successes since the end of World War II.

Mr. Nixon was also credited for his diligent efforts to establish detente with the Soviet Union, including achievement of a strategic arms limitation agreement. Although he did sharply reduce U.S. troop strength in Vietnam and get peace negotiations under way, he failed to extricate the United States from the war as he had indicated in the 1968 campaign he would do.

As the 1972 election campaign approached, Mr. Nixon was considered a strong favorite for re-election, especially when it appeared that the Democrats would nominate Sen. George S. McGovern of South Dakota, an outspoken critic of the Vietnam War painted as an ultraliberal by the Republicans.

Watergate

It was prior to Mr. McGovern's nomination that zealots in Mr. Nixon's re-election campaign -- the Committee to Reelect the President, soon known widely by its acronym as CREEP -- broke into the Democratic headquarters at the Watergate wearing surgical gloves, presumably to obtain information that could assure a resounding Nixon victory in November. The burglars were caught and almost at once tied to CREEP, but Mr. Nixon denied any knowledge of the affair.

Mr. McGovern sought to make a major issue of the break-in, but Mr. Nixon and his political strategists effectively finessed Watergate through the campaign, and the Nixon-Agnew team was resoundingly re-elected.

It first appeared that the Watergate cloud would pass with the trial, conviction and sentencing of the burglars. But one of the men convicted, James W. McCord Jr., wrote the judge, John J. Sirica, informing him that some of the witnesses had committed perjury.

Judge Sirica reconvened the grand jury in the case, and shortly afterward two separate investigative bodies started examining the matter, one under a special prosecutor and the other a Senate Select Committee.

Disclosures before the Senate committee particularly told of other misconduct in the White House and CREEP that included bribing of the burglars, earlier break-ins and electronic buggings of officials and private citizens, all in a climate of deep White House suspicion and hostility toward political opponents, anti-war critics and the news media.

Mr. Nixon's two principal White House aides, H. R. "Bob" Haldeman and John Ehrlichman, were forced to resign and later were convicted of improper conduct in the Watergate and related matters. In all, 25 persons went to jail, including Attorney General John Mitchell.

White House tapes

A dramatic break in the case came on July 16, 1973, when a former White House aide, Alexander P. Butterfield, disclosed the existence of an extensive tape-recording system in the Oval Office that had captured Mr. Nixon's conversations at the time of the Watergate break-in and thereafter.

The disclosure set off a lengthy and torturous battle between Mr. Nixon and the Senate committee over release of the tapes that finally went to the Supreme Court.

Written transcripts of the tapes, which were made public, created a sensation. They revealed Mr. Nixon in private to be consumed by his Watergate dilemma and profane in conspiring with his closest aides about ways to turn aside the legitimate inquiries of the special prosecutor and the Senate committee.

The controversy was complicated in the summer of 1973 when Justice Department investigators in Maryland uncovered evidence that Mr. Agnew, when he was Baltimore County executive and governor, had taken kickbacks from contractors doing business with the county and state, even after becoming vice president. Mr. Agnew denied the allegations, but the investigators built a strong case, and Mr. Richardson decided to seek an indictment.

Agnew departs

By this time there was talk of the possible impeachment of Mr. Nixon, and in some quarters Mr. Agnew was seen as a sort of "insurance policy" for Mr. Nixon. That is, as long as the highly controversial Mr. Agnew remained first in the line of succession to the presidency, there would be less pressure to depose Mr. Nixon.

In the end, however, Mr. Richardson informed Mr. Agnew that he faced indictment, and after much bluffing Mr. Agnew agreed in October to a plea-bargain to escape a jail sentence. In return for pleading no contest to one charge of income-tax evasion and resigning from the vice presidency, Mr. Agnew was let off with a suspended sentence.

Mr. Nixon quickly nominated House Minority Leader Gerald R. Ford, as his new vice president, in the first use of the 25th Amendment on succession.

Two weeks after Mr. Agnew's resignation, another sensational development rocked the Nixon presidency. As the special prosecutor, Archibald Cox, pressed the White House for the release of all its tape recordings, Mr. Nixon suddenly on Oct. 20 ordered Mr. Richardson to fire him. Mr. Richardson refused and resigned, as did his deputy, William Ruckelshaus. Solicitor General Robert H. Bork, becoming acting attorney general, did Mr. Nixon's bidding.

'Saturday Night Massacre'

The dramatic events immediately came to be known as "the Saturday Night Massacre" and convinced many in Mr. Nixon's own party that he had abused his office and would have to be removed. The House Judiciary Committee began hearings into possible impeachment. As Mr. Nixon continued to balk at release of the tapes, the Supreme Court ruled unanimously against him, and he finally acceded to the order.

The tapes, particularly one of a conversation in the Oval Office six days after the break-in, showed that Mr. Nixon was already actively engaged in trying to cover up the affair, and attempting to use the FBI and CIA in the process. It was this "smoking gun" that finally swayed holdouts on the Judiciary Committee to call for Mr. Nixon's impeachment.

Faced with this situation, and advised by close party associates that he had no alternative, Mr. Nixon announced on the night of Aug. 8, 1974, that he would be resigning the following day because, he said, the furor made it impossible for him to continue the work of his administration.

Resignation

"It has become evident to me that I no longer have a strong enough political base in the Congress," he told a television audience of more than 100 million.

The next morning he delivered a brief letter of resignation to Mr. Kissinger, then secretary of state. And after a long, rambling and largely maudlin farewell to his supporters in the East Room of the White House, he and Mrs. Nixon boarded a presidential helicopter on the South Lawn for the last time. He waved his familiar gesture of both arms aloft, fingers in the victory sign, and flew off to political exile at his home in San Clemente, Calif.

Just as in 1960 and 1962, when his two defeats at the ballot box had inspired the writing of his political obituary, his political demise was pronounced once again. But after several years of depression and illness, the ever-tenacious and resilient Mr. Nixon once again was on the road to personal resurrection as a foreign policy author and kibitzer. In 1980, he moved back east, to New York and then to a New Jersey suburb, to be nearer his children and a more active public life.

A voice unstilled

But the stigma of Watergate and his resignation never left him. While he was hailed by Republicans and Democrats alike for his bold opening to China, his own party never invited him to any of the five national conventions it held after he left office. Still, he would not be ignored. As recently as last month he was in Russia meeting with critics of President Boris N. Yeltsin -- and being rebuffed by Mr. Yeltsin for doing so.

Addressing the Oxford Union in 1978, Mr. Nixon said: "So long as I have a breath in my body, I am going to talk about the great issues that affect the world. I am not going to keep my mouth shut. I am going to speak out for peace and freedom." From beginning to end, Richard M. Nixon, in triumph and in defeat, insisted on being heard -- until he finally met the one adversary who could at last keep him down, and silence him.

WHAT HE SAID

To listen to excerpts from three of former President Richard M. Nixon's speeches call Sundial, the Sun's telephone information service at (410) 783-1800.

The three speeches include: "Checkers" speech in 1952; excerpts from the Kennedy-Nixon debate in 1960; and from his farewell speech to the White House staff on Aug. 9, 1974.

In Anne Arundel County call 268-7736; in Harford County, 836-5028; in Carroll County, 848-0338. Using a touch-tone phone, punch in the four-digit code 6200 after you hear the greeting.