Barack Obama will make history Thursday becoming the first black man to accept the Democratic presidential nomination.
His acceptance, which will be made before a crowd of 75,000 supporters, falls on the 45th anniversary of Martin Luther King Jr.'s "I Have a Dream" speech.
"Hope and change will be defined tonight," Democratic strategist Peter Fenn told CTV's Canada AM on Thursday from Denver, Colo., where the party's convention is being held this week.
He said Obama will draw a contrast between the past and the future and between himself and Republican candidate John McCain.
John Fund, a political journalist with The Wall Street Journal,said Obama's speech is going to add "meat to the bones" of his campaign platform.
"I suspect this crowd is going to be very surprised at how specific Barack Obama is going to be about his economic and social platform because much of it has been vague," Fund told Canada AM.
"Much of what Obama has been able to do so far has been carried forward by his charisma and his unique experience as the first African-American nominated for president."
On Wednesday, Obama made a surprise appearance at the Democratic National Convention after being introduced by his running mate Sen. Joe Biden and his wife, Jill.
"Change in America doesn't start from the top down," Obama told the crowd. "It starts from the bottom up."
Clinton unites party
Earlier in the night, former U.S. president Bill Clinton delivered a speech meant to restore party unity.
"Everything I've learned in my eight years as president and the work I've done since, in America and across the globe, has convinced me that Barack Obama is the man for this job," he said.
Some reports indicate Clinton felt the Obama camp hadn't been respectful of his legacy as the last Democratic president.
Clinton, who was an inexperienced and young politician when he was elected president in 1992, noted the similarities between himself and Obama. He described them both as forces of change.
"Obama is on the right side of history," Clinton said.
He also took numerous shots at the Republicans, noting how he gave them record surpluses when he left office and under George W. Bush, the U.S. now has a record debt.
"The Republicans will elect a good man," Clinton said of Sen. John McCain, before criticizing him as being "more of the same."
After Clinton, Biden spoke of his working-class background, comparing his own life to Obama's humble beginnings.
Biden, who ran against Obama during the primary races, said the two men share the same values and belief in the American dream.
"You can learn an awful lot about a man campaigning with him, debating him, and seeing how he reacts under pressure. You learn about the strength of his mind. But even more importantly, you learn about the quality of his heart," said Biden.
"I watched how he touched people, how he inspired them, and I realized he has tapped into the oldest American belief of all: we don't have to accept a situation we cannot bear. We have the power to change it. And change it is exactly what Barack Obama will do."
Biden repeatedly echoed Obama's trademark theme of change, using it to attack McCain, who he called a friend and referred to by his first name.
"As oil companies post the biggest profits in history, nearly half a trillion dollars in the last five years, John wants to give them another $4 billion in tax breaks. That's not change -- that's the same," he said.
On Thursday, singers Sheryl Crow, Stevie Wonder and will.i.am are scheduled to perform ahead of Obama's speech at Mile High stadium.
Academy Award-winner Jennifer Hudson will sing the national anthem.
With files from The Associated Press
