Edward Kennedy, who has died following a battle with a brain tumour at the age of 77, possessed the full mixture of the virtues, and the vices, that defined America's most famous political dynasty.
Edward Kennedy - one of the most influential politicians of his generation
The assassination of his brothers, John and Robert, placed a massive burden of expectation on his shoulders which he found difficult to live up to.
Yet, despite the shadow of Chappaquiddick, he became a respected elder statesman of the Democratic Party, and a champion of liberal causes in the US Senate.
Edward Moore Kennedy was born in the Boston suburb of Brookline on 22 February 1932, the youngest of nine children of Joseph P Kennedy and his wife Rose Fitzgerald Kennedy.
His Irish American parents were both from wealthy political families and his father served as the US ambassador to the UK prior to World War II.
After attending private schools in Boston, Kennedy went on to Harvard in 1950, but was expelled a year later after it was discovered that he had cheated in a Spanish exam.
He was the youngest of a political dynasty which fascinated America
He joined the army, serving at the SHAPE headquarters in Paris, before being readmitted to Harvard and graduating in 1956.
In 1960 his brother John was elected US president, vacating his Massachusetts seat in the Senate.
Edward was unable to stand for the seat until he was 30, so his brother asked the state governor to allow a Kennedy family friend to see out the end of John's term.
Although perfectly legal under the constitution, it gave rise to the accusation that Ted Kennedy had been gifted his Senate seat.
Edward was duly elected senator for Massachusetts in a special election in 1962, a post to which he would be consistently re-elected until the end of his career.
Tragedy stalked the Kennedy family; Edward's oldest brother Joe was killed during the war and, in 1963, John was assassinated as he drove through Dallas.
The following year Ted Kennedy himself was badly injured in a plane crash, leaving a legacy of back problems which dogged the rest of his life.
In 1968, Ted's brother, Robert, to whom he was particularly close, was assassinated in Los Angeles in the middle of his campaign for the Democratic presidential nomination.
There were expectations that Ted would take on his brother's mantle as a presidential candidate but his political career was about to be dealt a major blow.
Chappaquiddick ended his hopes of the White House
On July 18 1969, he was at a party on the small Massachusetts island of Chappaquiddick with a group, including six women known as the boiler room girls, who had worked in his brother Robert's presidential campaign.
Kennedy left the party, supposedly to drive his brother's former secretary, Mary Jo Kopechne, to catch the last ferry back to the mainland but, instead, the car turned onto a side road and crashed off a bridge into a tidal creek.
Kennedy pulled himself from the upturned car and, after swimming across a narrow creek, returned to his hotel without reporting the accident.
It was the following morning before local fishermen found the sunken car and discovered the body of Mary Jo Kopechne still inside.
Evidence given at the subsequent inquest suggested that she had probably remained alive in an air pocket for several hours and might well have been saved had the alarm been raised at the time.
Kennedy pleaded guilty to leaving the scene of an accident, claiming that he had been in shock, and was given a two-month suspended jail sentence.
Kennedy on Chappaquiddick
An inquest, held in secret at the request of Kennedy family lawyers, cast serious doubts on Kennedy's story, but no further action was taken.
This led to suspicions of a cover-up and the incident effectively ended any hopes Kennedy had of attaining the White House.
Chappaquiddick did not prevent his supporters urging him to run for both the 1972 and 1976 presidential nominations but he refused, citing family concerns about his personal safety.
He finally took the plunge in 1980, standing for the Democratic nomination against the incumbent president, and fellow Democrat, Jimmy Carter.
Kennedy's presidential bid
Kennedy hoped to capitalise on the country's economic woes, which had seen Carter's approval ratings slide.
But a poorly-managed campaign and a lacklustre appearance in a major TV interview ended Kennedy's hopes.
His refusal to concede the contest led to the divisive 1980 Democratic Convention where Kennedy tried, unsuccessfully, to persuade delegates committed to Carter to swap sides.
With his presidential hopes over, Kennedy began to rebuild his political career as a champion of liberal causes.
His mastery of senate procedure and his growing status in the Democratic Party made him a formidable voice in any debate, and his support was sought by political friends and opponents alike.
This is the cause of my life... Now the issue has more meaning for me - and more urgency - than ever before, but it's always been deeply personal, because the importance of healthcare has been a recurrent lesson throughout most of my 77 years
He became a master of coalitions, a pragmatist who would often work with his Republican opponents to get legislation through Congress, for example, the Quayle-Kennedy Training for Jobs Bill.
Despite his Catholic background, he abandoned his previous opposition to abortion and advocated a woman's right to choose.
He was also one of a handful of senators who supported the concept of same-sex marriages, his own state of Massachusetts becoming the first to give a legal framework to such unions.
He campaigned in support of better rights for immigrants to the US and was a consistent advocate of tighter gun control.
Mindful of his strong base of Irish American support, he originally backed the concept of a united Ireland and, in 1971, called for the withdrawal of British troops.
However his views had moderated by 2005, when he publicly snubbed the Sinn Fein leader Gerry Adams following the murder of Robert McCartney, and hosted a visit to Washington by the sisters of the dead man.
In 2006, Time magazine named him as one of America's "Ten Best Senators", saying that he had "amassed a titanic record of legislation affecting the lives of virtually every man, woman and child in the country".
He was a master of senate procedure
Such was his standing as the elder statesman of the Democratic Party that his endorsement was eagerly sought by aspiring presidential candidates.
In 2004 he supported his fellow Massachusetts senator, John Kerry, who went on to lose to Republican George W Bush.
Kennedy cited Barack Obama's opposition to the invasion of Iraq as one of the main reasons he endorsed the young senator from Illinois for the 2008 nomination, a statement seen as a direct snub to Mr Obama's chief rival, Hillary Clinton.
He was also reported to have been angry at some of the more outspoken comments by former President Bill Clinton in support of his wife Hillary's campaign, and he ignored pleas from the Clinton camp to remain neutral.
Kennedy said that he had always planned to support the candidate "who inspires me, who inspires all of us, who can lift our vision and summon our hopes and renew our belief that our country's best days are still to come."
Kennedy saw the young senator he backed triumph in the presidential election and was present on 20 January 2009 when Mr Obama was sworn in as the 44th US president.
Under the new administration, one of his most cherished causes took centre stage. The senator was seen as a key dealmaker in Mr Obama's efforts to push through his flagship healthcare reform plan.
The issue had become especially poignant for Kennedy, who was diagnosed with a malignant brain tumour in May 2008.
A week before his death, he wrote to Massachusetts Governor Deval Patrick asking him to change the law so that a replacement could be found for him immediately after his death.
Analysts suggest that he feared a lengthy gap could deny Democrats a crucial vote on the reforms.
Edward Kennedy sometimes failed to meet the huge expectations placed upon him following the deaths of his older brothers.
But his commitment to what he called their "justice, excellence and courage" ensured he guarded their memory fiercely and, despite his flaws, he left a substantial political legacy.
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