Barack Obama paraded a trio of Kennedy clan endorsements, evidence that large sections of the Democratic Establishment are now severing ties with the dominant force in the party for 16 years — Hillary and Bill Clinton.

The backing from Ted Kennedy, the veteran Massachusetts senator, is a huge prize for Mr Obama, providing him with momentum before next week’s “Super Tuesday” elections, as well as a magnet for votes in sections of the electorate where Mrs Clinton is strongest — Hispanics, blue-collar workers and Democratic loyalists.

At a rally at the American University in Washington, Mr Kennedy made a series of thinly veiled references to the clashes with the Clintons over recent weeks. He said that Mr Obama would represent a break with “cynical” tactics of “demonising” opponents.

“With Barack Obama we can turn the page on the old politics of misrepresentation and distortion,” he said. “We can close the book on the old politics of race against race.”

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Mr Kennedy is understood to have been repulsed by Mr Clinton’s alleged use of racial politics in the past fortnight. In one recent phone call, when the former President pleaded with him to stay neutral in the contest, Mr Kennedy “ripped into him”, according to a source close to the senator.

He is also said to regard a remark by Mrs Clinton that appeared to give President Johnson — disliked by the Kennedys — the greatest credit for civil rights legislation, as a “direct repudiation of the work of his family”.

Mr Obama was joined on stage not only by the late President’s daughter, Caroline, and his surviving brother, Ted, but also, unexpectedly, by his nephew, Congressman Patrick Kennedy.

Mr Kennedy usually refers only sparingly to his assassinated brothers, John and Robert. But yesterday he said: “There was another time, when another young candidate was running for president and challenging America to cross a new frontier. He faced criticism from the preceding Democratic President, who was widely respected in the party,” Mr Kennedy said, referring to Harry Truman.

“And John Kennedy replied, ‘The world is changing. The old ways will not do. It is time for a new generation of leadership.’ So it is with Barack Obama.” Mrs Clinton, who was speaking yesterday in the Kennedys’ back yard of Massachusetts, has pointed out that she has picked up support from the children of Robert Kennedy, Robert Jr, Kathleen Kennedy Townsend and her sister, Kerry.

Others say that Senator Kennedy has not proved infallible in selecting winners. In 1992 he initially backed Paul Tsongas against Mr Clinton, before gratefully receiving his help in a tough Senate re-election battle two years later against Mitt Romney — now a Republican candidate. In 2000 he supported Al Gore and in 2004 was a key figure in John Kerry’s campaign.

Mrs Clinton has the edge in backing from colleagues in the Senate and governors. Support from Antonio Villaraigosa, the Mayor of Los Angeles, has been critical in winning votes of Hispanics in Nevada this month and will be so in California next week.

There has been alarm within her campaign at the endorsements that Mr Obama has, which include senior senators such as Mr Kerry and Patrick Leahy, and those representing key Super Tuesday states, such as Claire McCaskill. Mr Obama even received the backing yesterday of the author Toni Morrison, who once labelled Mr Clinton the “first black President”.

The Democratic leadership is said to have become increasingly concerned about Mr Clinton’s behaviour, while many senior figures on Capitol Hill have privately made it plain that they have little affection for his wife. In committee meetings, Mrs Clinton has often put noses out of joint by overriding seniority rules and asking if she can speak first because she has another engagement. “Senators are busy people; they all have something else to do,” one long-time adviser said.

A dark cloud on Mr Obama’s horizon, however, continues to be Antoin “Tony” Rezko, his former friend and fundraiser, who faces trial on fraud charges next month. Yesterday, Mr Rezko was arrested by federal agents for violating bail conditions.

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