Herblock, 91, the Washington Post cartoonist whose witty, satirical and frequently ferocious drawings provided some of the most memorable images in the history of American political discourse and earned him the highest honors of his profession and the nation, died last night at Sibley Memorial Hospital. He had pneumonia.

His career began before the stock market crash of 1929 heralded the Great Depression and lasted into the 21st century. Herbert L. Block, in illustrations of stunning power and simplicity, illuminated and helped to define the great issues of the age: the rise of Hitler and the spread of fascism and dictatorship in Europe and Asia in the 1930s; World War II; the Cold War; the sea changes that marked American life in the postwar era; the collapse of the Soviet Union; and the prosperity and scandals of the Clinton years in the 1990s.

He chronicled every president from Herbert Hoover to George W. Bush. He coined the term "McCarthyism" for the smear tactics of Sen. Joseph R. McCarthy, the red-baiting Wisconsin Republican who was eventually censured by the Senate. His drawings of a fat and patient humanoid A-bomb encapsulated the menace of nuclear weapons.

He took the side of the have-nots of the world against the haves. He favored civil rights and candor in government. He distrusted all efforts to curb constitutional rights. He believed in the values underlying democracy: freedom, justice, equality.

Some of his earlier cartoons seem topical even today. He favored campaign finance reform, environmental protection and gun control decades before they became part of the nation's political agenda. A former cigarette smoker himself, he was a critic of the tobacco industry even before he quit.

On local issues, he supported home rule for the District of Columbia. In the 1960s and again in the 1980s, he helped preserve a public golf course in East Potomac Park, where he was a regular player, when the Interior Department had other uses for it.

At a time when issues tended to be framed in television sound bites, his cartoons provided trenchant and highly accessible commentary on the day's events. The Herblock cartoon was the first thing many readers looked for in their newspapers, whether they agreed with him or thought he was outrageous.

Herblock won three Pulitzer Prizes for editorial cartooning in his own right and shared a fourth Pulitzer with The Post for its coverage of Watergate, the scandal that forced Richard M. Nixon to resign the presidency under threat of impeachment. He received five prizes for cartooning from Sigma Delta Chi, the professional journalism society, as well as numerous other honors and half a dozen honorary degrees.

In 1994, President Bill Clinton awarded him the Presidential Medal of Freedom, the nation's highest civilian honor.

The Washington Post was Herblock's base for more than half a century, and through syndication he reached newspaper readers all over the United States and in several foreign countries. He wrote a dozen books, including "Herblock: A Cartoonist's Life," which was published in 1993.

In 1950, he had a one-man show at the Corcoran Gallery of Art, and President Harry S. Truman was among those who attended. A half-century later, in 2000, the Library of Congress mounted a retrospective exhibition of his work.

Herblock is represented in the Rosenwald Collection of the National Gallery of Art. And he was honored in the mid-1960s with a commission to design a postage stamp commemorating the 175th anniversary of the Bill of Rights.

Some of Herblock's most famous cartoons involved Nixon, whom he pictured crawling out of a sewer on one occasion and to whom he offered a clean shave on another.

But he considered all presidents, Democrat or Republican, to be fair game. He showed Lyndon B. Johnson carrying a bullwhip while striding past cowering White House aides under the caption, "Happy Days on the Old Plantation," and he drew Gerald Ford going both ways on the question of tax increases or cuts. A vacillating Jimmy Carter was shown complaining that he could not get a clear picture of himself on television.

In a cartoon on the Iran-contra arms-for-hostages scandal, President Ronald Reagan looked resolute on television while actually kneeling at the feet of the Ayatollah Khomeini and offering him a handful of money. During the 1988 presidential campaign, a two-faced George Bush was depicted under the caption, "Which Lips Are We Supposed to Read?" In 1997, Clinton was shown saying, "True, I Had Coffee With Those Big Contributors, but I Didn't Swallow."

President Dwight D. Eisenhower, whom Herblock faulted for allegedly insufficient support of the civil rights movement and lack of zeal in curbing the excesses of McCarthy, canceled his subscription to The Washington Post. Nixon did likewise. In 1967, Johnson dropped plans to give Herblock the Medal of Freedom. In 1970, Vice President Spiro T. Agnew dismissed him as "a master of sick invective."

Although his work appeared on the editorial page of The Post, Herblock made no effort to conform to the newspaper's editorial policies. His cartoons expressed the view of no one but himself.

In 1952, when The Post backed Eisenhower for president and Herblock backed Democrat Adlai E. Stevenson, the cartoons were dropped by the paper for a few days but then were restored in the interest of expressing diverse views. In 1968, when an editor removed the caption from a cartoon on gun control, the cartoonist threatened to resign. He soon received assurances that this would not happen again.

In a tribute on Herblock's 50th anniversary at The Post, the late Katharine Graham, a former publisher of the newspaper and chairman of The Washington Post Co., wrote:

"My mother had a saying, 'Any man worth marrying is impossible to live with.' Why does this make me think of my glorious life and times with Herblock, one of the greatest ornaments to The Post and to all of journalism? Underneath his genius for cartooning and writing lies a modest, sweet, aw-shucks personality. Underneath that lies a layer of iron and steel. For publishers and editors over him -- or under him, as it would be more accurate to say -- it's like having a tiger by the tail.

"He fought for and earned a unique position at the paper: one of complete independence of anybody and anything. Journalistic enterprises run best when writers and editors have a lot of autonomy. But Herb's case is extreme. And because he's a genius, it works."

Herblock was a cartoonist in the tradition established by William Hogarth in 18th-century England. He was compared to Honore Daumier, who chronicled the misfortunes of 19th-century France and was imprisoned for a caricature of King Louis Philippe; to Thomas Nast, inventor of the elephant and donkey symbols for the Republican and Democratic parties and scourge of Boss Tweed, the 19th-century New York political operator who made Tammany Hall a byword of corruption; and to David Low, who created "Colonel Blimp" to represent conservatism in 20th-century Britain. Herblock acknowledged the influence of Nast on his own work.

In a review of "Herblock: A Cartoonist's Life," John Kenneth Galbraith described the author as "the greatest cartoonist of his time" and went on to speak of his "unyielding political and social view." He added that "while he appreciates virtue, his real interest is in awfulness. When he sits down to his drawing board, his mind turns to the rascals, the phonies and the frauds."

In an essay in the catalogue of his Library of Congress show, Herblock wrote that a "political cartoon is not a news story and not an oil portrait. It's essentially a means of poking fun, for puncturing pomposity." He added that cartoons and stories serve the same purpose of helping readers understand situations.

"In opposing corruption, suppression of rights and abuse of government office, the political cartoon has always served as a special prod -- a reminder to public servants that they ARE public servants," he wrote.

"That is the relationship of the cartoonist to the government, and I think the job is best performed by judging officials on their public records and not on the basis of their cozy confidences."

Herblock said he got his ideas by reading the newspaper until he found some item that caused him to say, "They can't do that, for crissake!"

The task of transforming this sense of outrage into a cartoon involved several preliminary sketches and informal consultation with one or more reporters who had expert knowledge of the issue at hand. If he was doing a cartoon about the defense budget, for example, he would talk to the Pentagon correspondent.

"Such help -- not 'ideas for cartoons,' but background information and relevant facts -- is of enormous value," he said.

Having decided what he wanted to do, he set about making a final drawing. He always pressed his deadlines and rarely left the paper at night until he had a chance to see a page proof with his cartoon on it.

There is no place where Herblock's qualities as a cartoonist were more evident than in his various depictions of Richard Nixon. The only meeting between the two occurred at a cocktail party in the early 1950s. But from the time Nixon arrived in Washington in 1947 as a freshman congressman from California until his death in 1994, no one embodied better than Nixon what Herblock disliked most about government. In turn, no one represented what Nixon hated most in the news media more than Herblock.

Nixon was elected to the House of Representatives in 1946 in a campaign in which he accused Rep. Jerry Voorhis, the Democratic incumbent, of being a communist. When the election was over, he told a Voorhis aide that he knew the communist charge was false but that he used it simply because he had to win.

When he got to Washington, Nixon joined the House Un-American Activities Committee. He launched his career as a national politician with his successful pursuit of Alger Hiss, a well-regarded former State Department official who eventually was convicted of perjury in connection with allegations that he had spied for the Soviet Union.

By the time Nixon came to Washington, Herblock had been a critic of HUAC for a decade and had nothing but disdain for Nixon's brand of anti-communism. In May 1948, he published his first cartoon about the congressman. It showed him and two companions dressed as Puritans setting a fire under a chained Statue of Liberty. The caption said, "We've Got to Burn the Evil Spirits Out of Her."

In 1950, Nixon was elected to the Senate, defeating Rep. Helen Gahagan Douglas in a campaign in which he played the communist card by calling her a "pink lady." In 1952, he was elected vice president under Eisenhower.

As Nixon gained in prominence, there were more and more cartoons. On Oct. 29, 1954, there appeared the cartoon of Nixon climbing out of a sewer to address a political rally. In his autobiography, Herblock said that he had drawn it because Nixon was conducting "a mud-slinging, Red-smearing campaign against some of the most respected senators up for reelection [and] it occurred to me he was traveling the country by sewer. It described what he was doing."

At one point during his vice presidency, Nixon asked a Post reporter to give Herblock his regards and added: "You know, a lot of people think I'm a prick, but I'm not."

For 20 years, Herblock pictured Nixon with a five o'clock shadow. But when the Californian won the presidency in 1968, his nemesis decided to drop this practice on the grounds that "at a time of national division and crisis" an incoming president "was entitled to his chance to lead." So he drew a cartoon showing a barber chair and a sign saying, "This Shop Gives to Every New President of the United States a Free Shave. H. Block. Proprietor."

When Nixon introduced his Cabinet, he warned Cabinet wives that they would have to get used to seeing Herblock cartoons in their papers every morning.

The honeymoon did not last long. The Nixon administration fought opposition to the Vietnam War and tried unsuccessfully in 1971 to halt publication of the Pentagon Papers, a secret official history of the war.

In August 1972, when Nixon was running for reelection, Herblock did a cartoon in which the president is talking to a voter while holding a sign saying, "Secret Election-Year Plans to End the War." A tombstone looms in the background bearing the legend, "20,000 American Dead Since 1968."

On June 17, 1972, five men were arrested as they were trying to break into the offices of the Democratic National Committee at the Watergate office building. It soon developed that they had White House connections. Nixon called the incident a "third-rate burglary" and denied any effort to interfere with the investigation of it.

During a Senate hearing in July 1973, it was learned that Nixon had taped most of the conversations that had taken place in the Oval Office. Although he refused to release some of the tapes on grounds of executive privilege, others did become public. One had an unexplained 18-minute gap in it.

In a speech at Walt Disney World, Nixon declared to a group of newspaper editors: "I am not a crook."

On July 24, 1974, a unanimous Supreme Court directed Nixon to turn over all of the tapes to a special prosecutor. On Aug. 6, Nixon released transcripts showing that he had approved efforts to cover up the Watergate probe. He resigned three days later.

Herblock published dozens of cartoons about Nixon during these events. One of the most famous appeared in May 1974. It showed a malevolent Nixon dangling precariously between two spools of recording tape on which are written the words, "I Am Not a Crook."

When Nixon resigned, The Post ran a full page of Herblock cartoons on Watergate. At the top there was a quotation from the Oval Office tapes: "Years ago when I was a young congressman, things got under my skin. Herblock the cartoonist got to me. . . . But now when I walk into this office I am cool and calm."

Time never softened Herblock's image of Nixon. He remained impervious to the former president's efforts to rehabilitate himself. The last Nixon cartoon appeared in June 1991, when the Nixon library was opened with restrictions on access to some materials for various journalists. Nixon is shown with his feet entangled in some tapes, the transcripts of which had just been released. On one of them he is asking an aide whether the Chicago Seven antiwar protesters are all Jews.

Herblock concluded a chapter on Nixon in his autobiography by quoting Sen. Barry Goldwater of Arizona, a conservative icon and a former Republican presidential candidate: "He was the most dishonest individual I ever met in my life."

Herbert Lawrence Block was born in Chicago on Oct. 13, 1909, the youngest of three boys in the family of David Julian Block and Tessie B. Block. His father was a chemist who had a number of successful businesses. His mother was a prizewinning cook and the winner of a national contest for her slogan, "Milk from contented cows," for the Carnation Milk Co.

The boy showed such a talent for drawing that when he was 11, his father enrolled him in Saturday classes at the Chicago Art Institute. He won a scholarship for an additional term and also won several newspaper drawing and coloring contests.

He gravitated to the news business as naturally as he did to the world of art. His father had been a reporter as a young man, and one of his brothers was a reporter for the Chicago Tribune. He did drawings and a column for his high school paper and began to send items to Richard Henry Little, who was in charge of the extremely popular contributors' column at the Tribune.

Readers who submitted material to the column often signed themselves with their initials, as did Little himself, or with a pen name. At the suggestion of his father, the youngster combined his first and last names and thus became Herblock.

In 1927, he tried out with the Chicago City News Service, then a legendary breeding ground for journalistic talent, and was offered a job. Sorely tempted, he nonetheless decided to enroll in Lake Forest College. The school had no art program, but he spent two happy years studying and doing illustrations for college publications and a suburban newspaper.

In the spring of 1929, he left college to take a job with the Chicago Daily News. His first cartoon appeared April 24, 1929, and showed tree stumps stretching over hills to the horizon under a caption that read, "This Is the Forest Primeval -- ." He was not yet 20 years old.

The Chicago in which he grew up, like much of the rest of the country, was dominated by the Republican Party. As a teenager, he contributed cartoons to various GOP organizations, and in his autobiography he explained that this involved "no sacrifice of principle" -- the prosperous late 1920s seemed to be "the best of all possible worlds [and] everything, including the party in office, was fine." His father voted for Herbert Hoover for president.

All of this changed with the stock market crash in October 1929 and the rise of fascist and communist dictatorships in Europe and Asia in the 1930s.

As the country struggled to extricate itself from economic chaos, Herblock supported the New Deal of President Franklin D. Roosevelt. But he decried the demagogic radicalism of the likes of Huey Long, the "Kingfish" who ruled Louisiana as governor and U.S. senator, and Father Charles Coughlin, the anti-Semitic "radio priest" from Royal Oak, Mich. He also ridiculed Roosevelt's plan to pack the U.S. Supreme Court with enough new members to guarantee a majority of justices in favor of New Deal programs.

In foreign affairs, he was an internationalist at a time when much of the country was isolationist. Japan's incursion in Manchuria and China frequently drew his attention. In 1933, he showed a jack-booted Hitler, newly come to power as chancellor of Germany, parading past four glowering figures labeled "Coercion," "Intolerance," "Bigotry" and "Ignorance."

In 1933, Herblock left the Chicago Daily News and moved to Cleveland to join the Newspaper Enterprise Association, a Scripps-Howard feature service.

In the late 1930s, he ridiculed efforts of Britain and France to appease the German dictator with territorial concessions at the expense of other countries. As war clouds gathered with the threat of enormous casualties, he drew a cartoon of a boy asking a friend, "What are you going to be if you grow up?"

At a time when renewal of the draft law passed Congress by only a single vote, he pushed hard for U.S. support for Britain and France in the war against Hitler. One cartoon showed Charles A. Lindbergh, the heroic aviator and a founder of the America First Committee, vainly trying to turn back planes carrying supplies to the democracies.

In 1942, he was awarded the Pulitzer Prize for his body of work that year. A cartoon that was singled out in the citation showed a German soldier searching the sky over occupied France while a group of Frenchmen look on with glee. The caption said, "British Plane."

From 1943 to 1946, Herblock served in the Army and turned out posters. In 1946, he moved to Washington and joined The Post. He was already an established figure in journalism, and his hiring by Katharine Graham's father, Eugene Meyer, who had bought The Post at a bankruptcy sale in 1933, was regarded as a coup.

In 1954, Herblock won his second Pulitzer Prize for a cartoon on the death of Stalin. It showed the Grim Reaper greeting the Soviet tyrant with the words, "You Were Always a Great Friend of Mine, Joseph." The third Pulitzer, awarded in 1979, was for the cartoonist's life's work.

Away from the drawing board, Herblock was cheerful and accessible and given to such homey expressions as "Golly," "Hey, ho," and "Hey, there." His pleasures included golf and a vacation residence by the ocean in Delaware. He did not marry and leaves no immediate survivors.

Herblock, who published his last cartoon in The Post on Aug. 26, never retired or lost his enthusiasm for his work. He concluded his autobiography with these words: "There's always a clean slate, a fresh sheet of paper, a waiting space, a chance to have another shot at it tomorrow.

"Tomorrow!"

Herblock reacts to an ovation at the opening of his Library of Congress exhibition in 2000.