Former Sen. John Edwards, D-N.C., endorsed Sen. Barack Obama, D-Ill., for president in a dramatic attempt to help Obama answer concerns about his lack of support from white, working-class voters.
The move is seen as a major blow to Sen. Hillary Clinton, D-N.Y., who has rebranded herself during the course of the presidential campaign as a fighter for the working-class.
"I am fired up!" a beaming Obama told a large crowd at a campaign rally in Grand Rapids, Mich., Wednesday night.
Saying he felt bad about not being able to campaign in Michigan prior to now, Obama said he wanted to give voters in Michigan something special and introduced "my friend, John Edwards."
After walking out to an ecstatic crowd and to Bruce Springsteen's "The Rising," Edwards said, "During the course of this presidential campaign I have gotten to know the presidential candidates very, very well," he said. "Now, we're here, down to two amazing candidates."
Before explaining his decision, Edwards was booed by the crowd when he said he wanted to talk about "our friend, Sen. Hillary Clinton."
"What I've learned, and I've gotten to know her very well, is that she believes with every fiber of her being that America can be a better place and that we need change," he said.
"It is very, very hard to get up every day and do what she's done," he said. "It is hard to go out there and fight and to speak up when the odds turn against you ... what she has shown is strength and character ... she cares deeply about the working people in this country.
"She is a women who, in my judgment, is made of steel," he said. "And she's a leader in this country, not because of her husband, but because of what she has done."
After praising Clinton to meek applause, Edwards began explaining why he's decided to back Obama.
"Americans have made their choices and so have I. ... There is one man that knows and understands that this is a time for bold leadership ... there is one man who knows in his heart that it is time to create one America -- not two, and this man is Barack Obama."
Edwards said the Illinois senator stands with him in a fight to cut poverty in half within 10 years.
An Edwards aide told ABC News' Raelyn Johnson that it was only in the last day or two that Edwards made up his mind to endorse Obama, citing the fact that the race is over and the Democratic Party needs to focus on the fall.
Mark Kornblau, a former Edwards aide, told ABC News that Edwards' decision to endorse was not easy and that he continues to have great admiration for Sen. Clinton.
"The reason that he's doing this is that he thinks Sen. Obama is going to be a great president," said Kornblau, who said he spoke to Edwards hours before his announcement. "He's going to be a great candidate for the Democratic Party and ... it's time for the party to unite around Sen. Obama and focus on winning in the fall."
Kornblau says indecision was a factor in Edwards' timing, which was seen by some as sluggish.
"I think it was clearly a very difficult decision and that's part of the reason that he waited for so long," Kornblau said. "But it's now become clear that Sen. Obama is going to become the nominee and Sen. Edwards feels that it's important that the party rally around the nominee [and] focus on beating John McCain in the fall."
The announcement also came after Clinton's 41-point victory in the West Virginia Democratic primary Tuesday.