Rep. Patrick Kennedy, left, Sen. Barack Obama, Caroline Kennedy and Sen. Edward Kennedy greet the audience at American University in Washington, D.C. yesterday after the three Kennedys announced their support of Obama’s presidential bid.

Getty Images / Chip Somodevilla

WASHINGTON

Sen. Barack Obama claimed the presidential endorsement of two generations of Kennedys yesterday in a scene that evoked the spirit of political heroes past and rallied a youthful crowd to his call to “change the course” of the nation’s future.

“It is time again for a new generation of leadership,” Sen. Edward M. Kennedy declared in a speech at American University that echoed the flourishes of John F. Kennedy, Martin Luther King Jr. and Abraham Lincoln. “It is time now for Barack Obama!”

For his part, Obama said he was too young to remember the late president and was a child when Robert F. Kennedy ran for president. “But in the stories I heard growing up, I saw how my grandparents and my mother spoke about them — and about that period in our nation’s life as a time of great hope and achievement.”

The crowd — including many first-time voters — cheered as Kennedy called out with a grin, “I feel change in the air!” That was his nod to an Obama campaign byword that other candidates from both parties have begun to work into their speeches.

The Massachusetts Democrat’s embrace, according to his son, Rep. Patrick J. Kennedy, was the party’s equivalent of the “Good Housekeeping Seal of Approval,” a powerful signal to party insiders and to groups of Democratic voters that Obama needs to attract.

The elder Kennedy’s speech was also barbed with apparent rejoinders to rival candidate Sen. Hillary Rodham Clinton and her husband, former President Bill Clinton. Their recent criticisms of Obama have raised some eyebrows in the party and reportedly angered Senator Kennedy, its best-known liberal champion.

Onstage with Obama and Edward and Patrick Kennedy, a Rhode Island Democrat, was Caroline Kennedy, the daughter of the late president, who made a splash Sunday with her endorsement of Obama in an opinion article in The New York Times. Congressman Kennedy said Obama “brought a tear to Caroline’s eye” by describing how his father, a poor Kenyan, studied in America in part because of a Kennedy family foundation grant promoted by John Kennedy.

On the heels of a decisive victory Saturday in South Carolina, Obama now faces a rush of contests peaking next Tuesday — “Super Tuesday” — when a large fraction of nominating delegates will be chosen by voters in big and small states, coast to coast.

The endorsement ritual was timed to exploit its value in those elections and, perhaps, to discourage rival candidates from the kind of bickering that could divide the party in a political climate that many veteran Democrats view as favoring their side. Senator Kennedy took pains to pay respect to rival candidates Clinton and John Edwards, but he spoke several lines that could have been wrought specifically for the senator from New York and her husband.

Waving a disapproving finger at unnamed others, Kennedy said his first-term Senate colleague from Illinois knows how to enunciate his positions “without demonizing those who disagree.”

“We know the true record of Barack Obama,” said Kennedy. “When others were silent or simply went along, from the beginning he opposed the war in Iraq. And let no one deny that truth.” Hillary Clinton voted for the resolution approving the use of force in Iraq. Bill Clinton used the term “fairy tale” to critique the view that Obama’s antiwar record was unblemished.

Kennedy delivered one more double-edged line in his 20-minute speech with a smile — a jibe at Hillary Clinton’s assertion of her experience — and won knowing laughter in return: speaking of Obama, he said, “I know that he will be ready to be president on Day One!”

In a seeming jab at Bill Clinton, Kennedy recalled how another former president, Harry S. Truman, once gave unsolicited advice that another young presidential aspirant from the Senate, John Kennedy, passed up: “Be patient.”

The 46-year-old Obama also has “an uncommon capacity to appeal to the better angels of our nature,” Kennedy said, alluding to a famous speech by Lincoln. Kennedy said at another point that Obama “understands what Dr. Martin Luther King Jr. called ‘the fierce urgency of now.’ ”

Patrick Kennedy said the times call for a leader who, like President Kennedy, “can galvanize a new generation of voters to carry our nation forward.” He paid tribute to his father’s role in lowering the voting age to 18, drawing more cheers from the youthful crowd.

The younger Kennedy speculated in an interview that his father’s endorsement would help Obama with “entrenched institutional” forces in the party, labor leaders and major donors, for example. But he said a more telling influence might be with working-class and Hispanic voters who like Clinton but might now pause and take a second look at Obama.

For many students on hand yesterday, Obama has clearly made the sale.

“I think it’s really important to have a candidate who is not a Clinton or a Bush,” said Tara Fitzpatrick, an American University sophomore from Darien, Conn. “We don’t need a dynasty in the White House or running this country.”

Fitzpatrick thinks the boost from the Kennedy clan could make “a huge difference” for Obama. “It will make a big difference for the common voter.” She reasoned that the Clinton campaign “has the high and mighty,” whereas “Obama is really taking it to the streets. It’s a really down-home campaign.”

Patrick Kennedy, who had endorsed Sen. Christopher J. Dodd, the now-departed Democratic candidate from Connecticut, said he decided to endorse Obama after conversations with his father and his cousin Caroline. When Bill Clinton called one day last week to seek his support for his wife, Patrick Kennedy said that he was still undecided and demurred. A series of phone calls followed from Clinton allies and donors in Rhode Island and around the country.

By Saturday night, when Obama called to seek his support, Kennedy said he had made up his mind and told the senator he would support his presidential candidacy.

jmulligan@belo-dc.com