The candidates campaign in Missouri and Michigan, respectively. The Republican's choice of Sarah Palin as running mate has given him a boost in polls.
Speaking in Flint, where the unemployment rate is 12%, Obama said McCain is attempting a wholesale makeover after running a campaign based on his Washington experience.
"John McCain and his running mate, Sarah Palin, at the [Republican] convention asserted that they were the agents of change," Obama said. "Now they're trying to repackage themselves. We've been talking about the need to change this country for 19 months. I guess it must be working because suddenly John McCain is saying 'I'm for change too.' "
With about eight weeks to go until election day, the candidates concentrated on battleground states. To counter Palin's increasing success with conservative voters, Democrats dispatched Hillary Rodham Clinton to Florida, another swing state, where she too stressed the economy.
Earlier today, Republicans attacked Obama for allegedly requesting nearly $1 billion in earmarks for his home state of Illinois, a figure sharply contested by the Obama campaign.
Alaska Gov. Palin again said that she had rejected an earmark for the so-called "bridge to nowhere," and the Obama campaign immediately retorted that Palin kept the more than $230 million for the bridge and used it for other transportation purposes.
Taking direct aim at Palin, Obama accused her of flip-flopping on her claim to have opposed the bridge that has become a symbol of government pork.
"She was for it until everyone started raising a fuss about it," said Obama, standing against a backdrop of hybrid SUVs. "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're looking for is someone who has been consistently calling for change."
In her appearance, Palin again praised McCain for backing the increase of U.S. troops in Iraq as an example of how he was willing to support unpopular positions.
Some in Washington saw the war as lost, she said, with no hope for any candidate "who would rather lose an election than lose the war," she said, using the McCain campaign applause line.
"But the pollsters and the pundits, they forgot one thing when they wrote him off," Palin said to cheers today. "John McCain refused to break faith with the troops who have now brought victory in sight.
"I'll tell ya, as a mother of one of those troops, that's exactly the kind of man I want as commander in chief," said Palin, whose eldest son is heading to Iraq.
The latest polls show the general election essentially neck and neck, which was where it was before the party conventions. A CNN/Time poll showed the race deadlocked at 48%, largely unchanged from the previous week, when Obama led McCain by 49% to 48%.
But another poll by USA Today/Gallup, gave McCain a 4-point edge among registered voters and a 10-point lead among likely voters -- a big increase for McCain, who trailed Obama by 3 points among likely voters.
McCain senior aide Mark Salter said the campaign was thrilled about the numbers -- but cautioned that it was a post-convention bounce and that another milestone looms in the upcoming debates.
"Obviously we had successful convention. People were reminded of who John McCain is. I don't expect the Obama campaign to take it lying down. We have two months to go," Salter said.
"We're very confident that we've been able to use both his vice presidential choice and his convention to remind voters that John McCain's whole public career has been about change. We've been under siege that John McCain is running for George Bush's third term. We've successfully reminded people that this is who he is," he said.
So far, the polls indicate that whatever bounce the Democrats received after their convention last month was short-lived, at best. Republicans did get a bounce, generally attributed to the surprise choice of Palin as McCain's running mate.
The polls indicate a greater enthusiasm among the Republican faithful after the nomination of Palin, who appeals to conservatives who were lukewarm about McCain.
Democrats, responding to McCain's surprise pick of Palin, sent Clinton to Florida today for the second time in as many weeks to campaign.
With some Clinton supporters still angry that Obama did not select the New York senator as his running mate, aides said that Obama will lunch Thursday in Harlem with former President Bill Clinton while he is in New York to mark the seventh anniversary of the 9/11 terror attacks.
Campaigning in Kissimmee, Fla., Hillary Clinton focused on economic issues, a topic Democrats have made the centerpiece of their effort to tie McCain to the unpopular president.
Clinton argued that it was Democrats in the past who were eager to create jobs and improve the economy.
"Choosing a Republican to clean up this mess is like asking the iceberg to save the Titanic. It is not going to work," she said.
There's "a tough road ahead of us, a difficult election," she said. "People need to think hard about who will make the difference in your life. . . . People are working hard and falling further behind.
"Florida is critical and central Florida is the key to who wins Florida in November," she said, adding what has become one of her campaign taglines, "No way, no how, no McCain, no Palin."
Palin, at 44 the youngest and first female governor in Alaska's history, was originally to begin campaigning on her own this week. But she's proving a draw on the campaign trail, so the 72-year-old McCain decided to keep her at his side as they stump in battleground states such as Ohio, Pennsylvania and Missouri.
Palin's ability to motivate the Republican base also prompted Zondervan, the Christian book publisher owned by HarperCollins, to rush out a biography on the governor that will "explore themes from her career in politics, her life as a hockey mom, and her strongly held Christian faith," the publisher announced today. The book will be published Oct. 10.
peter.nicholas@latimes.commichael.muskal@latimes.comNicholas reported from the Obama campaign in Michigan and Muskal from Los Angeles. Staff writers Maeve Reston contributed from the McCain campaign in Lee's Summit, Mo., and Johannna Neuman reported from Washington,