Rallying a crowd Wednesday in North Carolina, the Democratic presidential contender said McCain will soon "be accusing me of being a secret communist because I shared my toys in kindergarten."
Obama also tried to turn around McCain's reliance on the argument of helping "Joe the Plumber." He's the Ohio man who gained national attention when Obama told him during a campaign stop that he wanted to "spread the wealth around."
Obama said people will be worse off under a McCain presidency whether they are "Suzy the student, or Nancy the nurse, or Tina the teacher, or Carl the construction worker."
Meanwhile, McCain said Wednesday that the country's economic problems will pass but that threats against the nation will not - and that Obama is not up to the task of protecting the United States.
In returning to the issue of national security, seen as McCain's strongest argument for his candidacy before the financial crisis overwhelmed the campaign, McCain stood with former military officers and national security advisers to ask rhetorically whether Obama had the wisdom and judgment to be commander in chief.
"The question is whether this is a man who has what it takes to protect America from Osama bin Laden, al Qaeda and the other great threats in the world," McCain said. "He has given no reason to answer in the affirmative."
"When that day arrives and the worries of economic crisis have fallen away, we will find awaiting our country all of the same great challenges and dangers that were there all along," he said. (Read more about McCain's statement in From The Road.)
McCain was spending his day competing for Florida's 27 electoral votes, considered crucial to his effort to assemble the needed 270. At a morning rally in Miami's Little Havana, he also continued his attacks on Obama over the economy. ()
"I have a plan to hold the line on taxes and cut them to make America more competitive," said McCain. Speaking at a Miami lumber yard that employs 100 people, down from 300 because of economic turmoil, he argued that Obama's economic plans would devastate small businesses.
"Sen. Obama and Sen. Biden ought to understand: Raising taxes makes a bad economy worse," McCain said. He warned that Obama's rhetoric masks a big-spending liberal politician.
"He can't do that without raising your taxes or digging us further into debt," said McCain.
And McCain has crafted a populist argument to deflect conservative criticism of his vote a $700 billion bailout of financial institutions. "I'm going to make sure we take care of the working people who were devastated by the excess and corruption of Wall Street and Washington," he said.
McCain also touted his plans to boost domestic offshore oil production, saying he said would leave the decision on drilling to the states but give them an incentive to increase production.
"We will drill offshore, and we will drill now," he said. "If we're going to drill off the state of Florida, you deserve more of those revenues. They shouldn't be sent to Washington, they should be sent to Tallahassee."
Republican vice presidential candidatealso talked about energy on Wednesday, calling for a "clean break" from the Bush administration's energy policies, which she says rely too much on importing foreign oil.
The Alaska governor said the recent drop in gas and oil prices shouldn't deter consumers and lawmakers from seeking alternative energy sources. She cast energy independence as a national security issue and said dependence on Middle East oil leaves the U.S. more vulnerable to terrorists.
"We not only provide wealth to the sponsors of terror, we provide high-value targets to the terrorists themselves," Palin said. "Across the world are pipelines, refineries, transit routes and terminals for the oil we rely on. And al Qaeda terrorists know where they are." ()
McCain at his rally also sought to energize the Cuban section of Miami, a devout Republican base, with derisive references to the Cuba's Castro brothers and ridicule of Obama's willingness to talk with hostile foreign leaders.
As for the Castro brothers, "We'll sit down with them right after they empty the political prisons," McCain said.
After his stop in North Carolina, Obama also heads to Florida where he is aiming for a one-man television blitz on Wednesday night, saturating prime-time with a 30-minute ad and popping up on the buzzy late-night TV scene.
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CBS News' Maria Gavrilovic reports that according to aides, the campaign is trying to gain midweek momentum that they hope will carry them through Election Day.
"For weeks now, Obama has been playing it safe, sticking to his message on the economy and defending his tax plan," reports Gavrilovic. "The campaign calls this "consistency" but for some voters, the end of the campaign season may have become a bit run-of-the-mill. The campaign hopes to change that today." (Read more from Gavrilovic)
The centerpiece of the effort is Obama's infomercial. It is rare for a candidate to buy a block of prime-time real estate to tell his story. Plenty costly, too.
The ad is expected to be a video montage of typical people talking about the challenges they face, with Obama explaining how he can help. A campaign adviser said the taped ad will feature a live cut-in to Obama, who is scheduled to be at a rally in Florida at the time.
The Obama team bought time on CBS, NBC and Fox for about $1 million per network. The spot airs at 8 p.m. EDT. It is also scheduled to run on Univision, BET, MSNBC and TV One.
Flush with cash from his record-shattering fundraising, Obama uses that advantage by buying up media time in ways that McCain cannot.
"What can $150 million raised in September do for a campaign?" writes CBSNews.com senior politics editor Vaughn Ververs in Horserace. "Well, for starters, it allows Barack Obama to put the pedal to the metal in the final week of the campaign and make it much more difficult for John McCain to stage what at this point would have to be considered a comeback." (Read more from Ververs)
McCain is purchasing loads of ad time, too. But the disparity between Obama and the Republicans is so wide that it has allowed Obama to spend in more states than McCain, appear more frequently in key markets and diversify his messages - some positive, some negative.
And negative is the tone for the latest Obama ad, a 30-second spot aimed at key states that uses McCain's own words against him and mocks Palin. Three quotes, one from 2005 and two from 2007, play off McCain's acknowledgment that he knows less about economic matters than other issues. In the last quote, McCain says he might have to rely on his vice president for expertise - and then the spot cuts to a winking Palin.
McCain countered with his own new ad Wednesday, dismissing Obama's infomercial as a "TV special."
"Behind the fancy speeches, grand promises and TV special, lies the truth," the McCain ad's announcer says. "With crises at home and abroad, Barack Obama lacks the experience America needs. And it shows. His response to our economic crisis is to spend and tax our economy deeper into recession. The fact is Barack Obama's not ready yet." (Read more about the latest ads and then watch them)
In addition to the paid television time tonight, Obama is also doing several interviews today. During a stop in Raleigh, N.C., Obama also will be interviewed by Charlie Gibson of ABC's "World News."
Later, in Florida, Obama will tape an appearance on Comedy Central's irreverent "The Daily Show" with Jon Stewart. The segment will run at 11 p.m. EDT.
Obama may even be competing with himself.
During the same 11 p.m. slot, Obama is scheduled to appear at a campaign rally for the first time with former president Bill Clinton, whose wife, Hillary Rodham Clinton, lost to Obama in the primaries.
The uniting of the former president and the would-be president in Kissimmee, Fla., is sure to draw live local and national television coverage.