Sen. Ted Kennedy, the stalwart lion of the Democratic Party for more than four decades, kicked off the party's convention tonight with a dramatic appearance that galvanized the crowd into an enthusiastic frenzy.
Striding confidently onto the stage of Denver's Pepsi Center, the ailing senator, who is recovering from brain cancer surgery earlier this year, waved and gave the thumbs-up sign to a sea of delegates waving Kennedy signs.
While the crowd alternately cheered and wipes away tears for several minutes, the last living Kennedy brother smiled and said, "My fellow Americans, it is so wonderful to be here."
Alluding to reports that his doctors were hesitant to let Kennedy travel to Denver, the senator roared, "Nothing, nothing is going to keep me away from this special gathering tonight."
"I have come here tonight to stand with you, to change America, to restore its future, to rise to our best ideals and to elect Barack Obama president of the United States."
Kennedy, relishing the applause and enthusiasm of the crowd, raised his voice to vow that "I will be there next January on the floor of the U.S. Senate when we begin," promising to help Obama pass legislation to make health care a fundamental American right.
In a poignant moment that seemed to represent the summation of the last few decades of American political history, the old warrior passed the torch to Obama and the new generation:
"There is a new wave of change all around us and if we set our compass through, we will reach our destination," Kennedy said.
Comparing Obama to his slain brother, John F. Kennedy, the senator shouted, "This November, the torch will be passed again to a new generation of Americans. Our country will be committed to his cause, the work begins anew, the hope lives on and the dream lives on."
That last line resonated with almost all Democrats, a dramatic echo of his closing words in his 1980 speech at the convention, "and the dream shall never die!" recognized as one of the most powerful speeches in recent American political history.
'Not a Dry Eye in the House'
While Kennedy stood and greeted fellow Democratic leaders, the crowd chanted his name and flashbulbs were popping.
"I can't put into words how meaningful it was," New York delegate Sheila Johnson told ABC News' Nitya Venkataraman. "He is the greatest senator in U.S. history."
She added that Kennedy's presence "reminds us as a party and as Americans what our core values are."
Brian Schatz, state chair of Hawaii's Democratic party, was equally moved: "It was thrilling. Not a dry eye in the house."
Schatz noted that Kennedy's speech was the ideal highlight of the convention's opening night. "For the younger generation, [it] drew a parallel between the Kennedy family and the Obama campaign," he said.
Kennedy was introduced by his niece, Caroline Kennedy, who lauded his "service and sacrifice," proudly describing him as a champion of the poor and dispossessed as she rattled off his achievements in Congress.
Caroline Kennedy, the daughter of President John F. Kennedy, said that "Uncle Teddy" and Barack Obama were two men who "have changed my life and the life of this country," emphasizing that Obama was the best heir to her uncle's "commitment to the timeless American ideals of justice and fairness, service and sacrifice, faith and family."
She introduced a video, directed by acclaimed documentary filmmaker Ken Burns, featuring images of Kennedy sailing, conducting an orchestra, reading to schoolchildren, greeting American troops and endorsing Obama last January.
Fellow political leaders ranging from civil rights pioneer Rep. John Lewis to fellow Massachusetts Sen. John Kerry lauded Kennedy, with Lewis recalling his "moral obligation to do everything possible to make this world a better place."
Longtime Delegates Recall Kennedy's Legacy
Kennedy's presence was highly anticipated by longtime Democratic delegates.
Joe Reed, 69, has been to every Democratic convention since 1968 and can't remember every skirmish, debate or cocktail party.
But he says he will never forget Sen. Kennedy's legendary "The Dream Will Never Die" speech in 1980, an eloquent defense of liberal ideas that is still the defining anthem for the party's left wing.
"As he built up to a climax, the crowd roared and took him and accepted him with all its heart," remembers Reed, the first black delegate from Alabama. "People were shouting and hollering -- that one will always stick out for me."
Reed, who is attending this week's convention in Denver, says he will be thinking of that speech and the Kennedy legacy when he gathers with his fellow delegates to nominate Barack Obama as their candidate.
"Kennedy's going to get the crowd stirred up," says delegate Eufaula Frazier, 83, a Miami civil rights activist who has been a regular at the party's conventions since 1972.
"He is one of the veterans of the civil rights movement and the progressive era, and Obama is the rookie who is picking it up and carrying it into the 21st century. There is so much history in this."
Kennedy's cancer struggle and his family's legacy are sure to make his appearance one of the highlights of the convention, especially in light of his dramatic endorsement of Obama in January that was considered one of the defining moments of the hard-fought Democratic primary.
"It will rally the troops," says Ted Sorensen, a speechwriter for Kennedy's brother, President John F. Kennedy, who is scheduled to give his own speech at the convention Tuesday.
"He is the lion of the Senate and the leader of the party's progressive forces," Sorensen says. "A shock and a shudder ran through the party when he was first hospitalized with the brain tumor, but this video appearance shows that he's not going away."
In addition to the 1980 speech, Sorensen said he remembers Kennedy's speech at his assassinated brother's Robert Kennedy's funeral in 1968 and at the Council on Foreign Relations to protest the Iraq War in 2004.
"He speaks clearly and powerfully, he's very natural on the platform, using many poetic allusions," Sorensen says.
Former New Jersey Gov. Brendan Byrne says he still recalls the threat that Kennedy posed to Carter's candidacy in 1980. "There is a magic about Ted partly because of our devotion to Jack, but he has a charm of his own.
"That electrifying speech worried the Carter people, even though the votes were already counted [in Carter's favor]," Byrne says. "It showed how much passion Kennedy could arouse. That cemented his reputation in the party."
Along with his eloquence, Kennedy's commitment to a liberal legislative agenda -- pushing through bills on health care and labor laws -- made him a force to be reckoned with in the party, especially during his primary battle with Jimmy Carter in 1980 and jousting with Bill Clinton's centrist leanings in the 1990s.
To some liberal members of Congress, such as Rep. Barney Frank of Massachusetts, tonight's appearance will be a bittersweet moment.
"He's always inspirational, but it will remind people that he is ill," he says, describing the degree of sadness among liberals in reaction to his sickness.
"Teddy has been our conscience. And it's almost like a family where one sibling has been taking care of an aging parent and now that sibling will not be around. What do we do now? He's virtually impossible to replace -- who's there for the poor, the sick?"
Kennedy's words tonight expressed his commitment to public service, says Reed of Alabama.
"It is a message that will resonate," he says. "And one will expect that when a Kennedy speaks, the world is going to listen."
ABC News' Rick Klein, Jake Tapper and Nitya Venkataraman contributed to this report