Edward Kennedy, the last of the Kennedy boys, died last week from a cancerous brain tumour diagnosed over a year before. The only brother to die a natural death, he was also the only one to live long enough to see his public image shift and change... several times.

Teddy went from being the irrelevant younger Kennedy, to a scandalous drunk, an aggressive legislator, a liberal anachronism, and then back, in more recent years, to being lauded as a master legislator and 'Lion of the Senate'. While his brothers John and Bobby remained fossilised icons of suave American liberalism, Teddy had the opportunity to live more, fail more and arguably achieve more than either.

He entered the public consciousness in the slipstream of his older brother. One way or another, a Kennedy boy was destined for the White House. Their father, Old Joe Kennedy, a third-generation Irish immigrant, had willed it. He made a fortune of money (allegedly) through bootlegging during prohibition, stock-market investments, the movie business and liquor importation. He later flirted with politics as Roosevelt's appointed chairman of the Securities and Exchange Commission ("Takes a crook to catch one," explained FDR) and then as ambassador to England (before his burgeoning Nazi sympathies and proclamations on the 'end of democracy' scotched his future prospects). By then Joe had made a lot of money and was intent on using it to groom his four boys for the White House.

After the death of eldest son Joseph in a wartime accident, the prospective presidential career went to Jack, and after a senatorial stint, America fell in love, not just with handsome Jack and his well-turned-out spouse, but with the whole dynasty – all the Kennedy boys and girls who could be seen in Life Magazine, relaxing at Joe's summer cottage in Hyannisport, the so called Kennedy compound.

Although the election of Kennedy represented for many the immigrant fairytale, the clan also buzzed with the excesses of American privilege. "I never felt the Great Depression firsthand," John admitted as he campaigned in 1960. "I learned about it at Harvard."

Teddy might not have even learned that much, having been expelled from Harvard in 1951 for having a friend take his Spanish exam. After this inauspicious start he served for two years in the army (but was steered away from service in Korea), was readmitted to Harvard, studied law at the University of Virginia, worked on his brother's campaign and got married to Virginia Joan Bennett, at which point he was essentially bequeathed John's senatorial seat when he vacated it to become president in 1960 (the seat was held by a family friend until 30-year-old Teddy was old enough to take it in 1962).

Teddy was accustomed to hand-me-downs. "We tried to keep everything more or less equal," said his mother Rose, in 1962, "but you wonder if the mother and father aren't quite tired when the ninth one comes along. You have to make more of an effort to tell bedtime stories and be interested in swimming matches. There were 17 years between my oldest and youngest child, and I had been telling bedtime stories for 20 years. When you have older brothers and sisters, they're the ones that seem to be more important in a family, and always get the best rooms and the first choice of boats and all those kinds of things, but Ted never seemed to resent it."

The Kennedy boys entered politics as pragmatic left-of-centre cold-warriors, fuelled by their father's ambition. But they were soon influenced, at least rhetorically, by the liberal winds of change blowing from the grassroots civil-rights movements of the 1960s. John was certainly talking the talk before he was murdered in 1963, and Bobby had begun walking the walk as a true leftist (despite being a McCarthyite in the '50s) when he was murdered campaigning for the presidency in 1968.

It's this liberal notion of what the Kennedys stood for, but didn't necessarily always embody, that Teddy embraced after their tragic deaths and this, coupled with a genuine interest in senate business which eluded his siblings, slowly made him a force to be reckoned with.

"The youngest son doesn't have the physical or mental abilities of the others, so the way he gets along is to be good, nice, easy to get along with," explained Milton Gwirtzman, a Washington lawyer who worked with the Kennedys. "When Ted got to Washington in 1963 he faced substantially the same situation in the senate, where many envious senators had sons older than he was then... But he made a point of calling them all 'Senator', and he learned how to have a drink of bourbon with Jim Eastland and address him as Mister Chairman, and they saw that he did his homework, that he was ready to take on the dirty work, like presiding over the senate, that nobody really likes, and after a while he was... people started to take to him here. His younger-brother characteristics stood him in good stead."

In fact, Ted was a credible presidential hopeful until, on the night of 18 July 1969, after a party on Chappaquiddick Island, he drove his car off a bridge, drowning 28-year-old Kennedy campaigner Mary Jo Kopechne. He didn't report the accident for a full day, and then pleaded guilty to fleeing the scene (but denied driving drunk or having a sexual relationship with Kopechne) and received only a two-month suspended sentence. He referred to the events as "irrational and indefensible and inexcusable and inexplicable" but generally kept quiet on the issue. Most tellingly, however, he chose to stay on as a senator.

This was the first serious crack in the image the Kennedys had created (though it wouldn't be the last). The Kennedy boys all had a penchant for boozy adultery but this had been mere rumour for most of the '60s. It was increasingly becoming part of the Kennedy mythology. Their privilege arguably gave the Kennedy brothers the sense of entitlement that drove both their political achievements and their personal failures, and although he didn't have the gall to run for the presidential nomination in 1972 or 1976, Teddy continued to serve despite the scandal. He balanced a life of hard partying and hard legislating throughout the '70s.

This is also, according to some, when his ideals really started to take shape. John and Bobby's liberalism is often exaggerated in retrospect, and in many ways Ted went farther down the left-wing path Bobby only got to hint at. In his role safeguarding the legacy of his brothers, some say he shaped them retrospectively in his own image. In reality, Ted could be said to have picked up his liberal ideals not from Bobby or Jack, but from The Great Society that Franklin D. Roosevelt inaugurated in the recessionary 1930s. And from the 1970s he stood at the forefront of those Democrats who saw themselves fulfilling the paternalistic welfare promises of the New Deal (just as a new generation of Republicans set out to dismantle it).

Politically ferocious

His political zeal was underpinned by a touch of denial. When he attempted to win the Democratic presidential nomination from Jimmy Carter in a bitter internecine conflict in 1980, his hopes were scuppered by the shadow of Chappaquiddick.

But he stayed politically ferocious. Through the Reagan-dominated '80s he maintained a reputation as a fearsome liberal senator, going against the Reaganomic tide in pushing women's issues, gay rights and welfare reforms, and in 1987 he made an important speech against the nomination of Supreme Court judge Robert Bork: "Robert Bork's America is a land in which women would be forced into back-alley abortions," he said, "blacks would sit at segregated lunch counters, rogue police could break down citizens' doors in midnight raids, schoolchildren could not be taught about evolution, writers and artists could be censored at the whim of government."

He was simultaneously, however, cultivating a reputation as a boozy womanising nightmare (a reputation not helped by his wife's drink problem, and his subsequent single status after he divorced her in 1982). Stories of his drunken antics (dancing on his own framed pictures in a Washington bar; accosting a distraught waitress in a well-known restaurant) dominated the gossip columns and by 1990 Michael Kelly could write: "Sometimes, especially in the evenings, he seems a Senator Bedfellow figure, an aging Irish boyo clutching a bottle and diddling a blonde."

A year later, Ted was to be embroiled in a more serious scandal when his nephew William Kennedy Smith allegedly raped a young woman after a night out with the senator. Kennedy Smith was acquitted, but not before the tabloids had a prurient poke through Kennedy's debauched lifestyle (ironically, Dominick Dunne, the writer who highlighted many of the more sordid elements at this time, died the day after Kennedy). To the Democrats, Ted Kennedy seemed to be an embarrassment; a quaint anachronism at best and, as Time Magazine put it, "a Palm Beach boozer, lout and tabloid grotesque" at worst. He responded by issuing a public apology for his behaviour and in 1992 married his second wife Victoria Reggie, who supposedly curbed his more self-destructive tendencies.

But as well as being sidelined for his personal issues, this was also the era when both sides of the chamber began to see wealth and prosperity as being facilitated by liberalised global markets and not by the government welfare programmes and civil-rights rhetoric that were Kennedy's stock in trade. Possibly fired up by this, he fomented his reputation as a relentless 'liberal lion', willing, where necessary, to work across party lines for beliefs many thought outmoded and irrelevant.

Healthcare reforms

During the Bush years it seemed the tide of history was leaving old-school liberals far behind, but the wiser, soberer Kennedy soldiered on. He voted against the Iraq war when many Democrats succumbed to hawkish war-mongering, and he continuously fought for the less privileged. And when the political tide turned again with a burgeoning recession and the prospect of a Democratic presidency, his New Deal politics suddenly seemed very relevant once again. His endorsement of Barack Obama over a disappointed Hillary Clinton was a key point in that election campaign. Furthermore, the healthcare reforms the Obama administration are currently pushing are very much in line with reforms Kennedy started seeking as far back as 1966. To some extent the '00s were when Ted Kennedy got his mojo back.

Michael Kelly, who characterised Ted Kennedy as a hapless boozer in 1990, said in the next sentence that he was "the leading voice of what is left of the Left in American politics, a lawmaker of great and probably increasing power, the self-appointed tribune of the disenfranchised, the patriarch of America's most famous political family and the world's most conspicuous Democrat".

And that still seemed true almost 20 years later. True, there's something not quite wholesome about the myth of Camelot that both shaped and tainted Ted Kennedy. The very notion of a political dynasty in a democratic country is suspect, and there's something spooky about the Kennedy machine, the sense of entitlement that drove it, the sordid realities behind it, and the sheen of regal glamour that covered it. But that political dynasty is probably now fizzling out (Ted's son Patrick is a congressman, but John's daughter Caroline's disastrous bid for a senate seat ended when she voluntarily stood down earlier this year).

Kennedy's legislative legacy, however, will live on. There are over 300 pieces of legislation with his name on them, many concerning woman's issues, gay rights, immigration law, healthcare and education. As ideologies shifted and changed around him, he stayed constant. He stuck to his guns and in the years leading to his death those guns were back in fashion. "To be truly human," he once said, "is to shape your own world." And for better and worse, Ted Kennedy did just that.