obama_mccain_3.jpgWASHINGTON (AP) _ Republican John McCain, lagging in the polls, was unable to gain ground in the U.S. presidential campaign in his second debate with Democrat Barack Obama.

With time running out _ only four weeks remain until the Nov. 4 election _ and U.S. and global financial institutions battered as badly as at any time in nearly eight decades, American voters appeared increasingly disinclined to put a Republican back in the White House, regardless of concerns about whether Obama, a first-term senator, has enough experience.

On a day when the U.S. stock market continued its precipitous decline, falling yet another 5.1 percent, the only new proposal McCain brought to voters in the Nashville, Tennessee, confrontation Tuesday night was $300 billion in additional government spending on sour mortgages _ a not particularly well-defined federal intervention that was unlikely to have sat well with his conservative base.

Both candidates stood back from the vitriol that was consuming the campaign in the days leading up to the town-hall forum at Belmont University, which snap polls after the give and take showed Obama had won.

CNN/Opinion Research Corp. put the debate in the Obama column by a margin of 54 percent to 30 percent. A CBS News poll of undecided voters gave the contest to Obama 29 percent to 27 percent. Going into the debate, the Gallup Poll daily tracking survey showed Obama leading McCain by 9 percentage points, 51-42, matching his largest lead over the veteran Arizona senator.

Obama running mate Joe Biden said Wednesday that his Republican rival's criticism of Obama as a friend of a domestic terrorist was part of an effort to inject fear and loathing into the campaign. Biden called Republican effort to tie Obama to 1960s radical William Ayers, in his words, “mildly dangerous.''

Beginning last weekend, Republican vice presidential candidate Sarah Palin has repeatedly claimed Obama is close to Ayers, a founder of the violent Vietnam-era group the Weather Underground. Obama and Ayers live in the same Chicago neighborhood and have served together on community boards. Obama has denounced Ayers' radical views and actions.

This presidential campaign, regardless of the outcome, will make history. At 72, McCain would become the oldest first-term U.S. president. Obama would be the first African American to hold the office.

They meet for their final debate on Oct. 15 at Hostra University in Hempstead, New York.

With the consensus showing Obama having outdistanced McCain in both debates so far, he headed Wednesday for a rally in Indiana, a Republican-leaning state where polls show him within a few percentage points of McCain. Biden, who took several days off to mourn the death of his wife's mother, was to campaign in Florida.

McCain and Palin, were planning stops in the key battleground states of Pennsylvania and Ohio, which McCain needs to win to have any chance of overtaking Obama.

In the debate, Obama quickly looked to link McCain to President George W. Bush, describing the financial crisis as the “final verdict on the failed economic policies of the last eight years'' that Bush pursued and McCain supported.

He contended that Bush, McCain and others had favored deregulation of the financial industry, predicting that would “let markets run wild and prosperity would rain down on all of us. It didn't happen.''

McCain blamed Obama and Democrats for the collapse of mortgage giants Freddie Mac and Fannie Mae, which helped trigger the unfolding economic crisis.

“They're the ones that, with the encouragement of Senator Obama and his cronies and his friends in Washington, that went out and made all these risky loans, gave them to people that could never afford to pay back,'' McCain said.

Obama responded: “I've got to correct a little bit of Senator McCain's history, not surprisingly. … In fact, Senator McCain's campaign chairman's firm was a lobbyist on behalf of Fannie Mae, not me.''

McCain campaign manager Rick Davis has a stake in a Washington lobbying firm that received thousands of dollars a month from Freddie Mac until recently.

McCain entered the debate in a precarious position because of his links to Bush, a fellow Republican.

That challenge has deepened with retirement accounts evaporating, tens of thousands of homes in foreclosure, unemployment climbing and the stock market plunging.

On national security, the candidates repeated familiar positions on Iraq. McCain chided Obama for opposing the buildup of U.S. troops in Iraq that is credited, in part, with reducing violence.

McCain said his rival “was wrong about Iraq and the surge. He was wrong about Russia when they committed aggression against Georgia. And in his short career he does not understand our national security challenges. We don't have time for on the job training.''

Obama countered with a trace of sarcasm that he did not understand some things _ like how the United States could face the challenge it does in Afghanistan after spending years and hundreds of billions of dollars in Iraq.

“I don't understand how we ended up invading a country that had nothing to do with 9/11, while Osama Bin Laden and al-Qaida are setting up base camps and safe havens to train terrorists to attack us.''

The candidates were polite, but the strain of the campaign showed. During a discussion of an energy bill, McCain referred to Obama as “that one,'' rather than speaking his name.

By Wednesday morning, both campaigns had already released new TV ads.

Obama's new ad continued his criticism during the debate that McCain's health care plan included taxing employer-based health care benefits. “Instead of fixing health care, he wants to tax it,'' the ad says.

McCain's campaign, in turn, put out a TV spot contending that Obama promises nearly $1 trillion in new spending in the wake of the $700 billion financial rescue plan Congress approved. “Sound crazy? the ad asks. “It is.''