The Illinois senator told voters that the GOP convention speakers are spending all their time talking about politics, not about issues that matter to voters. He criticized the Republicans for not addressing the economic distress or housing foreclosures that have grown during the Bush administration.
Speaking with reporters later, Obama dismissed the idea that Alaska Gov. Sarah Palin, the GOP's vice presidential candidate, had been criticized unfairly because of her gender.
"The notion that many questions about her work in Alaska is somehow not relevant to her potentially being vice president of the United States doesn't make too much sense to me," Obama said.
"I assume she wants to be treated the same way guys are treated, which means their records are under scrutiny. I've been through this for 19 months. She's been through this for, what, four days so far?"
Asked by workers at a factory here about Palin's attacks on him Wednesday night, Obama replied, "I'll let Gov. Palin talk about her experience. I'll talk about mine."
Later, when reporters pressed him about Palin, Obama noted that his opponent is Republican John McCain, not the GOP vice presidential pick.
"By the way, I've been called worse on the basketball court. It's not that big a deal," Obama said.
Reporters shouted after Obama as he left the microphones for details about what he had been called. His reply: "You'd have to bleep it out."
Earlier in the day Obama's top strategist, David Axelrod, dismissed the Alaska governor's convention speech as dishonest about Obama's record.
Axelrod told reporters aboard Obama's campaign plane that the Republican National Convention speakers had distorted the Democratic candidate's record and ignored his resume. He also suggested that John McCain's running mate was only parroting what she'd been told.
"There wasn't one thing that she said about Obama or what he's proposing that is true," Axelrod said. "She tried to attack Sen. Obama by saying he had no significant legislative achievements. Maybe that's what she was told."
On Wednesday, Republicans sought to define Obama as untested and inexperienced, making light of his past work as a community organizer in Chicago.
Obama said the attack was weak.
"They're talking about the three years of work I did right out of college, as if I'm making the leap from two or three years out of college into the presidency," he told reporters.
Ultimately, Axelrod said, the Republicans squandered an opportunity to promote their candidate. He also questioned the emphasis on McCain's years as a prisoner of war, saying the Arizona senator's history already was well known.
"They're shedding an awfully lot of heat but no light," he said. "It almost defies the laws of physics."
As for Palin's claim to be a political outsider, Axelrod said that given her pointed criticism of Obama, "for someone who makes the point that she's not from Washington, she looked very much like she would fit in very well there."