FARMINGTON HILLS, Mich. (AP) - Listening to Barack Obama, it can seem like Republican vice presidential nominee Sarah Palin is the main person standing between him and the White House instead of John McCain.

Obama is putting as much heat on Palin as he is on the man at the top of the GOP ticket, objecting to the Republican Party's portrayal of her as a reformer who can bring change to Washington.

That is supposed to be Obama's distinction, and he's not taking kindly to Palin trying to claim it. Especially when it appears the new star on the GOP ticket is helping boost its standing: McCain has jumped to a dead heat or narrow lead over Obama in the latest national polls since choosing Palin as his running mate.

Obama said last week's Republican National Convention did a good job of highlighting Palin's biography — "Mother, governor, moose shooter. That's cool," he said. But he said Palin really is just another Republican politician, one who is stretching the truth about her record.

"When John McCain gets up there with Sarah Palin and says, 'We're for change,' ... what are they talking about?" Obama said Monday, arguing that they aren't offering different ideas from President Bush and they are just trying to steal his campaign theme because it seemed to be working.

"It was just like a month ago they were all saying, 'Oh, it's experience, experience, experience.' Then they chose Palin and they started talking about change, change, change," he said.

Obama's supporters appear to be just as fired up against Palin. In Farmington Hills, they booed when Obama first mentioned her name and laughed dismissively when he said she had a compelling biography. "Whatever," an audience member shouted.

In Dayton, Ohio, Tuesday, the crowd waiting for Obama to take the stage chanted "No pit bulls! No pit bulls!" — a reference to Palin's joke that lipstick is the only thing that sets hockey moms like her apart from the dogs.

Obama's campaign seemed to be caught off guard by McCain's surprise pick of Palin on Aug. 29. Obama's spokesman initially blasted her as a former small-town mayor with zero foreign policy experience who wants to continue Bush's policies. But Obama quickly walked the statement back with more congratulatory words about Palin as a compelling addition to the ticket.

Voters, particularly women, seem to agree, according to new polls. An ABC News-Washington Post survey showed white women have moved from backing Obama by 8 points to supporting McCain by 12 points, with majorities viewing Palin favorably and saying she boosts their faith in McCain's decisions.

Obama campaign manager David Plouffe said there's no doubt Palin is helping excite the GOP base, but what remains to be seen is how she plays with swing voters over the remaining two months of the campaign.

"There's no question they believe Governor Palin has given them a surge of energy in the short term," he said. "We'll see where we stand eight weeks from now."

With Palin out on the campaign trail every day blasting Obama, it became increasingly clear he had to respond and try to undermine her credibility. He was careful with his approach, declining in an interview on MSNBC's "Countdown" on Monday to respond directly to a question about whether she's too inexperienced to be next in line to the presidency.

But Obama's campaign saw an opening when the McCain-Palin campaign released a new ad Monday called "Original Mavericks" that included the claim that Palin stopped the so-called Bridge to Nowhere, a nearly $400 million proposal to build a bridge to an island in Alaska occupied by just 50 residents and an airport. Obama called the claim "shameless."

Palin voiced support for the bridge during her campaign to become Alaska's governor, although she was critical of the size, and later abandoned plans for the project. She used the federal dollars for other projects in Alaska.

"A bunch of heat started generating because people were thinking, 'Why are we building a bridge to nowhere?'" Obama said to laughter from a packed gymnasium of supporters in the Detroit suburb of Farmington Hills. Some booed at the mention of her name.

"So a deal was cut where Alaska still got the money. They just didn't build a bridge with it, and now she's out there acting like she was fighting this thing the whole time," he said, jabbing his fist in the air like a boxer. He released his own ad in response to the GOP spot that says McCain and Palin are "politicians lying about their records."

At an earlier stop Monday in Flint, Obama said of the bridge claim: "I mean, you can't just make stuff up. You can't just re-create yourself. You can't just reinvent yourself. The American people aren't stupid. What they are looking for is someone who has consistently been calling for change."

On Tuesday, The Washington Post reported that Palin has billed Alaska taxpayers for more than $43,000 in travel and lodging expenses for her children and husband during the 19 months she has been governor.

Sharon Leighow, a spokeswoman for the Alaska governor's office, told the Post that many of the invitations Palin receives also request that she bring her family. And the newspaper pointed out that Palin's travel expenses are far less than those of her predecessor, Frank Murkowski.

McCain-Palin spokesman Tucker Bounds said Obama's negative attacks show he is increasingly desperate.

"Senator John McCain and Governor Sarah Palin have shook up the establishment and delivered real reforms," Bounds said. "Barack Obama has a speech he gave in 2002."

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Associated Press writer Christopher Wills contributed to this report from Chicago.