“What McCain has done with Governor Palin's nomination is aim right at a demographic that Obama needs to address quickly: noncollege-educated women,” said Mike McCurry, a former spokesman in the Clinton White House. “They need to maximize Biden's ability to reach out to them, but at the end of the day, it is Obama who has to get that very, very critical group.”

While Obama did not aggressively challenge Palin, his advisers opened a new line of criticism to brand her as part of the Republican establishment.

“For someone who makes the point that she’s not from Washington, she looked very much like she’d fit in very well there when you see how she brings the attacks,” Axelrod said. “They all felt very familiar to Americans who are used to this kind of thing from Washington.”

Clinton advisers said that she stood ready to help the Obama-Biden ticket, but they urged the campaign not to overestimate Clinton’s impact, noting that she had other commitments this fall, like campaigning and raising money for Senate candidates. Obama aides said the Clinton trip had been in the works before Palin was named the running mate.

Still, Mo Elleithee, a Clinton spokesman, said he believed she could make a difference with some voters who feel lost in the current economy and who want to see a federal role enacting universal health insurance.

“Anyone who was inclined to support Hillary Clinton typically did so because of her focus on middle-class, bread-and-butter issues,” Elleithee said. “Her message for Barack Obama on those issues could certainly help the Democratic ticket at the ballot box.”