Richard N. Goodwin, an aide, a speechwriter and a liberal force for the Kennedys and Lyndon Johnson who helped craft such historic addresses as Robert Kennedy's "ripples of hope" and LBJ's speeches on civil rights and the Great Society, died Sunday evening at age 86.

Goodwin, the husband of Pulitzer Prize-winning historian Doris Kearns Goodwin, died at his home in Concord, Massachusetts. According to his wife, he died after a brief bout with cancer.

Goodwin was among the youngest members of President John F. Kennedy's inner circle and among the last survivors. Brilliant and contentious, with thick eyebrows and a mess of wavy-curly hair, the cigar-smoking Goodwin rose from a working-class background to the Kennedy White House before he had turned 30. He was a Boston native and Harvard Law graduate who specialized in broad, inspirational rhetoric — top JFK speechwriter Theodore Sorensen was a mentor — that "would move men to action or alliance."

Thriving during an era when few feared to be called "liberal," Goodwin also worked on some of President Johnson's most memorable domestic policy initiatives, including his celebrated "We Shall Overcome" speech. But he differed with the president about Vietnam, left the administration after 1965 and would later contend — to much debate — that Johnson may have been clinically paranoid.

President Lyndon B. Johnson prepares for his State of the Union address with, from left, Richard Goodwin, Jack Valenti and Joseph A. Califano, Jr. at the White House in Washington on Jan. 12, 1966. White House / AP

Increasingly impassioned through the latter half of the '60s, he co-wrote what many regard as then- Sen. Robert Kennedy's greatest speech, his address in South Africa in 1966. Kennedy bluntly attacked the racist apartheid system, praised protest movements worldwide and said those who speak and act against injustice send "forth a tiny ripple of hope."

Goodwin's opposition to the Vietnam conflict led him to write speeches in 1968 for Kennedy and to manage the presidential campaign for anti-war candidate Sen. Eugene McCarthy. But McCarthy faded, Kennedy ("My best and last friend in politics," Goodwin wrote) was assassinated and Republican Richard Nixon was elected president.

Goodwin never worked for another administration, although he and his wife were fixtures in the Democratic Party and he continued to comment on current affairs for Rolling Stone, The New Yorker and other publications. In 2000, he was called upon for one of the least glamorous jobs in speechwriting history: Al Gore's concession to George W. Bush after a deadlocked race that ended with a 5-4 Supreme Court decision in Bush's favor.

Goodwin was admired for his rare blend of poetry and political savvy, and criticized for being all too aware of his talents. Even one of his supporters, historian and fellow Kennedy insider Arthur M. Schlesinger Jr., would say that he "probably lacked tact and finesse." But Schlesinger also regarded Goodwin as the "archetypal New Frontiersman" of JFK's brief presidency.

"Goodwin was the supreme generalist," Schlesinger wrote in his Pulitzer Prize-winning "A Thousand Days," published in 1965, "who could turn from Latin America to saving the Nile Monuments, from civil rights to planning a White House dinner for the Nobel Prize winners, from composing a parody of Norman Mailer to drafting a piece of legislation, from lunching with a Supreme Court Justice to dining with Jean Seberg — and at the same time retain an unquenchable spirit of sardonic liberalism and unceasing drive to get things done."

Richard Naradof Goodwin was born in Boston on Dec. 7, 1931, but spent part of his childhood in suburban Maryland, where he would recall being harassed and beaten because he was Jewish. His enemies only inspired him. He graduated summa cum laude from Tufts University, at the top his class from Harvard Law School, then clerked for Supreme Court Justice Felix Frankfurter, the first of a series of powerful men Goodwin worked under.

His road to Kennedy's "Camelot" began not with an election, but with the corruption of TV game shows. He was an investigator in the late '50s for the Legislative Oversight Subcommittee of the U.S. House of Representatives, which helped reveal that the popular "Twenty One" program was rigged. Goodwin's recollections were adapted into the 1994 film "Quiz Show," directed by Robert Redford and featuring Rob Morrow as Goodwin, who was one of the producers. "Quiz Show" received four Academy Award nominations, including for best picture, but was criticized for inflating Goodwin's role in uncovering the scandal.

His efforts were noticed by Kennedy, then a U.S. senator from Massachusetts and aspiring presidential candidate. Goodwin was hired to write speeches for the 1960 race, advised Kennedy for his landmark television debates with Nixon and held a number of positions in the administration, from assistant special counsel in the White House to an adviser on Latin America.

When the president was assassinated in 1963, Goodwin took on a sensitive task — prodding the military to act upon Jacqueline Kennedy's wishes and place an eternal flame at the national cemetery in Arlington, Virginia.

Under Kennedy, Goodwin's most ambitious work may have been on the Alliance for Progress, a program of economic and social reforms meant to break the U.S. from its history of supporting dictators in Latin America. The Alliance was announced in March 1961 with a promise from Kennedy that the spirit would not be "an imperialism of force or fear but the rule of courage and freedom and hope for the future of man."

In the long term, the alliance had mixed results, as support dropped among subsequent administrations. In the short run, it was overshadowed by an imperialist fiasco, the Bay of Pigs invasion, the failed U.S.-backed attempt in April 1961 to overthrow Cuba's socialist government, led by Fidel Castro.

Goodwin had questioned the plan, but still had to answer for it. Not long after the Bay of Pigs, he met with Castro ally and finance minister Ernesto "Che" Guevara, the two of them sitting on the floor of a hotel room in Monte Video, Uruguay. They were both in town for an Inter-American conference that was to ratify the alliance.

"But, of course, when we started this conversation though, he said, 'Mr. Goodwin, I'd like to thank you for the Bay of Pigs,'" Goodwin recalled during a joint 2007 appearance with his wife at the John F. Kennedy library in Boston. "He said, 'We were a pretty shaky middle class, support was uncertain, and this solidified everything for us.' So what could I say? I knew he was right."

After Kennedy's death, Goodwin was urged — implored — to stay on by the new president: "You're going to be my voice, my alter ego," Goodwin remembered Johnson saying. There was constant tension between Johnson, a Texan, and the "Harvards" around Kennedy, but Goodwin initially had strong influence and was an essential shaper of LBJ's legacy.

He was assigned key policy speeches, including the 1964 address at the University of Michigan, when Johnson outlined his domestic vision of a "Great Society." Johnson's 1965 civil rights speech to a joint session of Congress is among the most famous presidential orations in history. It was written by Goodwin — within hours, he alleged — in the wake of the bloody marches in Selma, Alabama, and ended with an exhortation, drawing upon the language of the protest movement, that reportedly left the Rev. Martin Luther King Jr. in tears.

"Their cause must be our cause, too," Johnson said. "Because it is not just negroes, but all of us who must overcome the crippling legacy of bigotry and injustice. And we shall overcome."

Upon signing the Voting Rights Act in August 1965, Johnson gave the pen to Goodwin. But by then, LBJ had committed ground troops to Vietnam and Goodwin was personally and professionally estranged. He had become convinced, he later wrote, that "President Johnson's always large eccentricities had taken a huge leap into unreason."

"My conclusion is that President Johnson experienced certain episodes of what I believe to have been paranoid behavior," he wrote in "Remembering America," published in 1988. "I do not use this term to describe a medical diagnosis. I am not L.B.J.'s psychiatrist, nor am I qualified to be. I base my judgment purely on my observation of his conduct during the little more than two years I worked for him."

Goodwin's theory was widely debated. He was backed by Time magazine journalist Hugh Sidey, while former Johnson aide Jack Valenti said Goodwin was simply trying "to flog a book."

Goodwin was married for 14 years to Sandra Leverant, who died in 1972. Three years later, he married Doris Kearns, a former LBJ aide who became one of the country's most popular historians with such works as "Team of Rivals" and "No Ordinary Time." Goodwin had three children, one with his first wife and two with his second. Doris Kearns Goodwin is a frequent guest on MSNBC and "Meet the Press."

Goodwin's other books included "Triumph or Tragedy: Reflections on Vietnam," released shortly after he left the Johnson administration and "Promises to Keep." He also wrote a play, "The Hinge of the World" (later retitled "Two Men of Florence"), a drama about the clash between Galileo Galilei and Pope Urban VIII that reflected on the need to raise "poor, lowly creatures" from ignorance so they could "travel the Heavens."

"And how is this mighty liberation accomplished?" Goodwin wrote. "Not through holy text. By these hands, these eyes, this brain. The skull of a single being imprisons the power to unravel creation, to encompass and describe the entire world. Why, this teaches man they may regain our native, the dominion granted Adam in their days of innocence. Creatures who can accomplish this have such power, they are almost like Gods."