( dpa ) - He's been compared to two of the most charismatic US politicians - the ill-fated Kennedy brothers whose young careers were snuffed short by assassin's bullets.
Now, Democratic presidential hopeful Senator Barack Obama, 46, who beat his closest rival Senator Hillary Clinton by a 2-to-1 margin in Saturday's South Carolina party primary, is adding to his quiver the support of two members of the Kennedy family.
The backing from US Senator Edward Kennedy and Caroline Kennedy, the brother and daughter of former president John F Kennedy, has stirred excitement and controversy in the bitter struggle for the centre-left party's nomination.
Senator Kennedy - the surviving icon of the US left after president Kennedy's 1963 assassination and the subsequent murder of another brother who had his eye on the White House, senator Bobby Kennedy, in 1968 - was taking the unusual mid-primary step of publicly endorsing Obama Monday at a rally at American University in Washington.
Caroline Kennedy, who has kept a relatively low profile since her image was seared in the nation's conscience as a five-year-old at her father's funeral, threw her weight behind Obama on Sunday, with an essay in The New York Times, "A President Like My Father."
The Kennedy stamp of approval is one of the most prized endorsements in Democratic campaigns.
The endorsement went to Obama because of his ability to inspire "the way people tell me that my father inspired them," Caroline Kennedy wrote.
The move meant the Kennedys were turning their back on the Clintons, who are regarded as the nation's second most important Democratic family and who cultivated the Kennedy's support during Bill Clinton's 1993-2001 presidency.
It also spotlighted growing personality differences between the two lead Democratic candidates. Obama represents "our vision of ourselves as a nation," while Hillary often appears to be "delivering bitter medicine," said one Democratic Party activist, who spoke on condition of anonymity.
"We need the positive vision represented by Obama and the hard work that Clinton knows has to be done," said another Democratic activist, Sima Osdoby, who has endorsed Clinton. "We can't do one without the other."
The word "inspiration" creeps often into discussions about Obama, who has given rousing speeches about bringing together young and old, rich and poor, black and white and Hispanic.
In a recent debate, Obama said being president meant "having a vision for where the country needs to go ... and then being able to mobilize and inspire the American people to get behind that agenda for change."
In the same debate, Clinton said the job meant being a "chief executive officer (who must) be able to manage and run the bureaucracy."
Robert Reich, Bill Clinton's former secretary of labour, has thrown his support to Obama as have other former Clinton confidantes. In comments to the New Yorker magazine, Reich compared Obama to the late Robert Kennedy, who was shot down 40 years ago in California while campaigning for the Democratic Party's presidential nomination.
Reich told the New Yorker that Obama was like Robert Kennedy. The closer one got to the late senator, "the more you realized that his magic lay in his effect on others rather than in any specific policies."
The double Kennedy endorsements came after days of criticism of the increasingly strident role of former president Clinton in his wife's campaign.
He drew fire for comments that implied Hillary Clinton had lost the South Carolina primary because half the voters were black and supported Obama, who is also black. Bill Clinton on Saturday dismissed Obama's blockbuster win by noting that another African- American candidate, civil rights activist Jesse Jackson, had also won the state in past primaries.
In her essay, Caroline Kennedy said she did not mean to criticize the other candidates, but had to use the "rare moments" when someone like her father came along, for the good of the country.
"Over the years, I've been deeply moved by the people who've told me they wished they could feel inspired and hopeful about America the way people did when my father was president," she wrote. "That is why I am supporting a presidential candidate in the Democratic primaries, Barack Obama."