McCain sought to blunt Obama's campaign-closing pitch, lacking the funds to match it.

"He's got a few things he wants to sell you: He's offering government-run health care ... an energy plan guaranteed to work without drilling ... and an automatic wealth spreader that folds neatly and fits under any bed," McCain told an audience in Florida.

The Republican National committee on Wednesday unveiled a new ad that seeks to raise doubts about Obama's lack of executive experience. The ad will begin airing Thursday in Ohio, Indiana, Virginia and Florida markets.

"Would you go under with a surgeon who has never operated?" an announcer says. "Can you hand your nation to a man who has never been in charge of anything? Can you wait while he learns?"

Earlier in the campaign, former Democratic rival Sen. Hillary Rodham Clinton as well as McCain sought to raise doubts about Obama's relatively thin resume on foreign policy and national security matters.

In response, Obama traveled last summer to Iraq, Afghanistan and Europe, where he met with world leaders. Later, he tapped Sen. Joseph Biden, who has long experience in foreign policy, as his vice presidential running mate.

More recently, he won an endorsement from former Secretary of State Colin Powell.

Conversely, McCain has slumped in the polls as the economic crisis has unfolded in the past several weeks.

Speaking to reporters Wednesday, he said the economic meltdown, while serious, was temporary, and the nation would emerge stronger.

Besides Obama, he criticized the Democratic leaders of Congress, who hope to command larger majorities in the new House and Senate than they do now.

"We're getting only a glimpse of what one-party rule will look like," he said, predicting deep cuts in defense spending and efforts to shrink America's role in the world if Democrats take over the government.

"Let there be no confusion about the threats we face," said McCain. "I've had to make some defining choices along the way," he added in what seemed to be a reference to his time in the Navy, more than five years of which were spent as a prisoner of war in Vietnam.

Obama blended his sharp rhetoric with a more humorous approach as he sought to fend off McCain's charge that his tax policies amount to socialism.

McCain, he said, will soon "be accusing me of being a secret communist because I shared my toys in kindergarten."