From NBC/NJ's Aswini Anburajan
PITTSBURGH -- Obama called Pennsylvania Sen. Bob Casey's endorsement one of the most meaningful endorsements he's received on the campaign trail.
"You know, I did not press him on this endorsement, you know there were some people that I was nagging all the time," Obama said of reaching out to Casey. "Bob I thought to myself, there's great reason for me to press him; I told him I'd love to have his support, but I understood that you know we're behind in the Pennsylvania polls. I just want to say it would have been easy for Bob just to stay out of it, just to stay neutral. I think everybody would have accepted that.
"But when he called me and said, 'I think this is the right thing to do,' it meant as much to me as any endorsement that I've received on the campaign trail," Obama added.
Casey introduced Obama and spoke to the potential of his leadership.
VIDEO: Watch Pennsylvania Sen. Bob Casey's remarks while endorsing Barack Obama.
"This campaign is a chance for America, a chance for America to chart a new course, to go down a different path," Casey said of his endorsement. "A path, first of all, of change, a path of a new kind of politics, a path -- and finally a path of hope and healing."
He also said that he had spoken to Hillary Clinton, who's been endorsed by Gov. Ed Rendell, of his decision. "I want everyone in this hall today to know something," Casey said. "I called Senator Clinton last night to tell her my decision and she was very gracious. And we know that she's a great senator; she's a great leader."
He stressed that all Democrats were focused on winning the election in 2008 and heaped praise on Obama, saying that the "good Lord had blessed him with many gifts," adding that Obama had "the kind of judgment that's steady in the eye of the storm."
He will spend the next three days traveling with Obama through the state, an uncommon occurrence on the trail. Though Obama occasionally has surrogates with him, they rarely spend more than a day on the trail with him. He called Obama a "fighter," who started the race as an "underdog" -- something Pennsylvanians struggling with the economy understand well.
In a retooled and longer stump speech Obama spent a chunk of his time discussing the economy, emphasizing how the costs of the Iraq War have detracted from domestic priorities.
"If we can spend $10 billion a month rebuilding Baghdad, we can spend $10 billion rebuilding roads and bridges and schools right here in America," he shouted to wild applause.
He hit Clinton on her ties to special interests and repeated a version of a line he's given before, that the platform she's running on wasn't one that could beat McCain in a general election.
"Senator Clinton makes an argument about electability: 'Well I, you know, I'm the person to take on John McCain.'" Obama said of her argument. "Now, the polls don't show that, but the argument is that because she's been around in Washington longer that somehow that makes her better equipped, and I've gotta explain. Look, if the contest between McCain and the Democratic nominee is who's been there longer, John McCain wins! John McCain wins!"
The audience at the War Memorial Center was clearly on Obama's side, chanting "Yes We Can!" and Obama's name repeatedly before and after he spoke.