Obama will head to Florida to prepare for Friday's event at the University of Mississippi.
If Obama can hold his own on foreign policy, it could ease those worries, aides said Sunday as they tried to lower expectations for the first-term Illinois senator, a powerful speaker but an uneven performer in multiple debates during the Democratic primaries.
Instead, senior Obama adviser Robert Gibbs said it is McCain who needs to meet expectations.
"John McCain has boasted throughout the campaign about his decades of Washington foreign policy experience and what an advantage that would be for him," Gibbs said. "This debate offers him major home-court advantage and anything short of a game-changing event will be a key missed opportunity for him."
While Obama is cloistered in Tampa, Fla., veteran Washington lawyer Greg Craig will play the role of McCain in the debate preparations. Craig was a member of President Clinton's defense team during the impeachment proceedings. In 2004, he was a stand-in for President Bush when Democratic nominee John Kerry prepared for his debates. Craig also has advised both Clinton and Secretary of State Madeleine Albright on foreign policy.
The bulk of Obama's time in Florida will be devoted to the debates, but he's also likely to hold some campaign events in the area.
Polls show a tight race in Florida. McCain won the state during the GOP primaries but Obama didn't compete there because of Democratic Party sanctions against Florida because it held its nominating contest too early in the season.
Obama and McCain are scheduled to debate three times between Friday and Oct. 15, sandwiched around one matchup between their running mates, Sen. Joe Biden and Alaska Gov. Sarah Palin.
But the opening presidential debate traditionally sets the tone for voters and it's often difficult for a candidate to overcome a poor performance. This debate also comes as the financial markets remain turbulent and the campaign rhetoric has shifted from foreign issues to domestic and economic concerns.
At an outdoor rally in Charlotte, Obama stayed focused on the turmoil on Wall Street, and laid blame at the feet of Republican policies he said McCain is committed to continuing.
"We're now seeing the disastrous consequences of this philosophy all around us, on Wall Street as well as Main Street," Obama said. "Yet Sen. McCain, who candidly admitted not long ago that he doesn't know as much about economics as he should, wants to keep going down the same disastrous path."
He criticized a $700 billion proposal by President Bush and congressional leaders to buy bad mortgage debt in an effort to unfreeze the nation's credit markets, calling it a "concept with a staggering price tag, not a plan." Yet he said the government had little option but to intervene.
And Obama said any bailout must include plans to recover that money, and protect working families and big financial institutions, and be crafted in a way to prevent such a crisis from happening again.
"Regardless of how we got here, we're here today and the circumstances we face require decisive action because your jobs, your savings and your economy are at risk," Obama said. "There must be no blank check when American taxpayers are on the hook for this much money."
McCain spokesman Tucker Bounds accused Obama of "offering absolutely no new ideas, policies or concrete solutions." "We cannot afford a directionless drive like Barack Obama," said Bounds.
Aides said Obama had spoken with Treasury Secretary Henry Paulson, Fed Chairman Ben Bernanke, congressional leaders and Bill and Hillary Clinton in fleshing out his approach to the bailout.
North Carolina is a Republican-leaning state Obama hopes to win in November. After the rally he was returning to Chicago for fundraising and a campaign swing through Wisconsin, a Democratic-leaning state he needs to win.
Separately, Obama is pulling his campaign staffers out of North Dakota, where he had been making an effort to become the first Democrat to carry the state in 44 years. Obama spokeswoman Amy Brundage said the campaign will send workers from his 11 offices in North Dakota to other battleground states.
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