DENVER -- Democrats opened their national convention on Monday with two speakers who moved the crowd to tears and raucous cheers.

Both Sen. Ted Kennedy and Michelle Obama spoke of their hope for the future and how that hope is embodied in Sen. Barack Obama, who is making a historic quest for the White House.

Michelle Obama stressed her husband's values and belief in the American dream as Democrats seek to reassure voters that the presidential candidate understands their problems.

She described her own blue-collar upbringing in Chicago and the hard work her parents put into raising a family. She said Barack Obama, though he was raised in a different part of the world, had a similar life and adopted the same beliefs.

"Barack and I were raised with so many of the same values, like you work hard for what you want in life, that your word is your bond," she said.

Ted Kennedy Electrifies Crowd

Earlier in the night, the ailing Sen. Edward M. Kennedy made an unexpected appearance, where he told a standing crowd at the Pepsi Center that this is "a season of hope" for a stronger future in America. His wave familiar, his voice firm, despite his struggle against brain cancer.

And he added: "I pledge to you that I will be there next January on the floor of the United States Senate."

That had special meaning given the bleak prognosis he faces with his disease.

"The hope rises again and the dream lives on," he said after his seven minutes at the microphone, minutes of high and unexpected drama for delegates waving thousands of Kennedy signs, cheering as he came and as he stepped away into the arms of his wife Vicki.

"My fellow Democrats, my fellow Americans, it is so wonderful to be here," he said. "And nothing, nothing is going to keep me away from this special gathering."

He flew to Denver Sunday night, and his first stop was a hospital, where doctors examined him. His physicians had been wary of the trip, especially his exposure to crowds, given the weakness of his immune system after weeks of chemotherapy and radiation treatments. The brain cancer was diagnosed after he collapsed in May in Hyannis Port, Mass. After brain surgery in June, he had remained at home, save for a brief trip to Washington to cast a Senate vote on July 10 for Medicare legislation that had been stalled in deadlock.

It was to have been a Kennedy appearance on tape, after a tribute by his niece, Caroline Kennedy. But he came himself, and his performance, if brief, was not frail.

"I have come here tonight to change America, to restore its future, to rise to our best ideals and to elect Barack Obama president of the United States," he said.

Kennedy's speech would have been standard convention fare, nothing remarkable, but for his health. It was a striking performance for a man of 76, stricken by cancer. "As I look ahead, I am strengthened by family and friendship," he said. "So many of you have been with me in the happiest days and the hardest days.

"Together we have known success and seen failure ... victory and defeat," he said. He said this is the time for victory, for the election of Obama. "For me this is a season of hope ... new hope ... and this is the cause of my life, new hope that we will break the old gridlock ..."

Caroline Kennedy said her uncle "has been a senator for all who believe that the dream has never died." She said "Uncle Teddy" and Obama are "two men who have changed my life and the life of this country.

"Leaders like them come along rarely," she said. "But once or twice in a lifetime, they come along just when we need them the most This is one of those moments."

She said that in this campaign Obama "has no greater champion" than Kennedy. "When he is president, he will have no stronger partner in the United States Senate," she said.

Kennedy is the last surviving brother of the late President John F. Kennedy and a party icon across more than four decades in the Senate.

Kennedy's decision to endorse Obama in the early days of the primary campaign was a turning point, not only because it was a ceremonial passing of the torch but also because of his ability to serve as a political reference of sorts for Hispanics, union workers and others.

Questions Linger About Clinton Delegates

The opening gavel fell at 3 p.m. Denver time, with Obama and Hillary Rodham Clinton still struggling to work out the choreography for the formal roll call of the states that will make him -- a 47-year-old senator bidding to become the first black president -- the party nominee.

"There is no doubt in anyone's mind that this is Barack Obama's convention," the former first lady told reporters. And yet, she said, some of her delegates "feel an obligation to the people who sent them here" and would vote for her.

However, there was little sign of open hostility or tension on the convention floor Monday. There weren't any homemade Clinton signs in the crowd and Clinton delegates weren't too vocal.

During the musical intermissions, the delegations of Florida and Delaware played with beach balls and danced.

By the end of the evening, the two camps had compromised.

Clinton and Barack Obama agreed to limit a divisive roll call for president, giving delegates a brief but historic choice between a black man and white woman.

The deal would allow some states to cast votes for both Obama and Clinton before ending the roll call in acclamation for the Illinois senator. Clinton herself may cut off the vote and recommend unanimous nomination of Obama, according to Democratic officials involved in the negotiations. They discussed the deal on condition of anonymity while details were being finalized.