DENVER — For inspiration, Barack Obama looked to John F. Kennedy, Ronald Reagan and Bill Clinton as he wrote -- and rewrote -- the speech he will deliver tonight at the Democratic National Convention.
But the historical weight of Obama's address to party loyalists packed into a football stadium exceeds anything faced by those soon-to-be presidents when they accepted their parties' nominations in 1960, 1980 and 1992.
In a nation defined by racial divisions since its founding, Obama is the first African American to win a major party's White House nomination.
He is delivering the speech on the 45th anniversary of Martin Luther King Jr.'s "I Have a Dream" address on the struggle for civil rights. And Obama's trademark -- for better or worse -- is emotionally charged speeches that inspire his followers.
The senator paid tribute to King's speech at a campaign stop in western Illinois this week. He called it "a seminal moment in American history."
"It gave voice to America's ideals in a way that has been done very rarely in any speech in American history," he said.
"I was 2 years old at the time, and I think it's fair to say that had it not been for, not just the speech, but the movement behind the speech, the sentiments behind the speech, the work and the toil and the risks that were taken by previous generations, then I wouldn't be in Denver on Thursday accepting the nomination for the presidency."
Whatever its historical significance, the shattering of a racial barrier will not be Obama's main focus tonight. Instead, a top advisor said, he will make his case, mainly in terms of the economy and foreign affairs, against Republican rival John McCain, the Arizona senator who is to accept his own party's presidential nomination next week.
"He's going to lay out the case for change," said David Axelrod, Obama's chief strategist. "He's going to set the stakes of this election, the risks of continuing down the road we're on, which is plainly what Sen. McCain is offering. And he's going to talk about an alternative path that's rooted in the best of what this country is, and the kind of future that we can build if we take it."
The speech's setting has drawn scorn from Republicans: a stage flanked by Greek columns on the 50-yard line of Invesco Field at Mile High, which seats 76,000 people for Denver Broncos games.
"Temple of Obama," the Republican National Committee called it in the latest installment of its "Audacity Watch" series of press releases on Obama. McCain's campaign has portrayed Obama as a celebrity who lacks the experience and judgment to lead the country.
Obama started work on the speech about four weeks ago, Axelrod said. He "kicked out the main draft," and then his chief speechwriter, Jon Favreau, and others offered suggestions.
"His mode of working tends to be that he writes things out in longhand, puts them in his computer, gathers string and then sits down and kicks out a draft and then circulates that to his group," Axelrod said. By Wednesday, Obama had virtually finished, but will be "refining it and buffing it up and working on it, I'm sure, right until the very end."