(Agencies)
Updated: 2008-08-29 11:47

DENVER -- Barack Obama cast his presidential nomination as proof that no dreams are too high, savoring a historic moment for himself and the nation Thursday before setting out on a difficult struggle to break another barrier for a black American.

Obama's success in obtaining the Democratic nomination was indeed a remarkable achievement, reached despite the misgivings of some Americans uncomfortable with electing the son of an African immigrant -- not "the typical pedigree," as he put it.

Democratic presidential nominee US Senator Barack Obama (D-IL) walks onstage to give his acceptance speech at the 2008 Democratic National Convention in Invesco field in Denver, Colorado August 28, 2008. [Agencies]

He used his acceptance speech at the Democratic National Convention in part to allay those concerns, to show Americans that he is one of them -- not born of wealth or privilege, his gains made of hard work and sacrifice.

"This moment -- this election -- is our chance to keep, in the 21st Century, the American promise alive," Obama said. He put himself in the shadow of great leaders like John Kennedy, Franklin Roosevelt and Martin Luther King, Jr., as well as his humble parents.

His speech was the culminating moment of the Democrats' four-day convention, the launching point for a difficult fall campaign against McCain.

The stakes could not have been higher -- for the future of this campaign and the past of racial politics. It came on the 45th anniversary of one of the greatest speeches in American history, King's "I Have a Dream" address.

An enthusiastic crowd of 84,000 -- unprecedented for a political convention -- literally shook the stadium at Invesco Field at Mile High with their stomping feet, every participant equipped by organizers with an American flag. More important was the audience of millions of Americans watching on television, a tougher crowd, as Obama spoke before a backdrop of columns reminiscent of the White House portico.

Looking for validation, Obama gave unknown Americans from battleground states prime-time speaking roles to explain their struggles and how the candidate could help them. And Obama himself highlighted the stories of working class Americans, the kinds of voters who have expressed wariness of his candidacy -- the woman about to retire in Ohio worried about health care costs, the Indiana worker who lost his job to competition from China, the veterans living on the streets or in poverty, the military families in the midst of repeat tours of duty.

He wanted them to know he was one of them. He said he sees his World War II veteran grandfather in the faces of veterans returning from Iraq and Afghanistan, recognizes his mother in the overworked student yearning to give her children a better life and hears his grandmother in the voice of the businesswoman facing workplace discrimination.

Democratic presidential nominee US Senator Barack Obama (D-IL) waves before his speech at the 2008 Democratic National Convention in Denver, Colorado August 28, 2008. [Agencies]

"I get it," Obama said. "I realize that I am not the likeliest candidate for this office. I don't fit the typical pedigree, and I haven't spent my career in the halls of Washington. But I stand before you tonight because all across America something is stirring. What the nay-sayers don't understand is that this election has never been about me. It's been about you."

For those voters with another concern -- that a first-term senator who just turned 47 isn't experienced enough to lead the country -- Obama had an answer, too, in a list of policy proposals that he argued would improve their lives. He promised tax cuts that would benefit workers, an end to dependence on Middle East oil, more funding for education, health care for every American and an end to the war in Iraq.

"America, now is not the time for small plans," Obama said.

And he tried to raise concerns about his rival, Republican John McCain, by saying he's too much like the unpopular President Bush.

"John McCain has voted with George Bush 90 percent of the time," Obama said. "I don't know about you, but I'm not ready to take a 10 percent chance on change."

With the nomination in hand, Obama could afford to pause -- if only for a moment -- to reflect on the path that took him from untested rising star at the Democratic convention just four years ago to the party's standard-bearer this time and a symbol of hope to millions of Americans yearning for change.

Obama himself took note of the transformation.

"Four years ago, I stood before you and told you my story -- of the brief union between a young man from Kenya and a young woman from Kansas who weren't well-off or well-known -- but shared a belief that in America, their son could achieve whatever he put his mind to."

Then he launched himself into the task at hand, persuading voters that he is the leader for "one of those defining moments -- a moment when our nation is at war, our economy is in turmoil, and the American promise has been threatened once more."

Obama didn't flinch from offering himself as ready not only for the title of president but also of "commander in chief."

"If John McCain wants to have a debate about who has the temperament, and judgment, to serve as the next commander in chief, that's a debate I'm ready to have," Obama said.