WASHINGTON (AP) — Democrat Barack Obama was playing to his strength on Monday with plans to unveil an economic rescue plan for middle class Americans, bidding to extend his lead in the polls ahead of this week's final presidential debate with Republican John McCain.

The scary U.S. economic picture has dominated the 2008 White House contest and those fears only grew last week as the stock market plunged nearly 20 percent, wiping away billions of dollars in retirement savings. Tens of thousands of Americans already have lost their homes to mortgage foreclosures and unemployment was on the rise.

McCain, who is perceived as having reacted unevenly through the economic storm, acknowledged on Sunday that the issue was hurting his campaign.

"We're a couple points down, OK, nationally, but we're right in this game," the veteran Arizona senator said to campaign volunteers assembled at his headquarters outside Washington. "The economy has hurt us a little bit in the last week or two, but in the last few days we've seen it come back up because they want experience, they want knowledge and they want vision. We'll give that to America."

A new Washington Post-ABC News poll showed Obama with a 10 point lead, 53-43 percent, among likely voters with an even larger 2-to-1 margin among voters who put the economy as the top issue in the campaign. The poll, conducted by telephone Oct. 8 to 11, had a margin of error of plus or minus 3.5 points for the sample of 766 likely voters.

Hoping to build on McCain's weakness, Obama planned what his campaign said would be "a major policy address to lay out his economic rescue plan for the middle class." The 47-year-old freshman Illinois senator was to appear in Toledo, Ohio, a critical swing state where the race may be decided. Polls show the contest there is close.

McCain, meanwhile, dialed back personal attacks on Obama over the weekend that have been prominent recently in the Republican campaign, but vowed he would "whip" his opponent's "you know what" in Wednesday's last debate of three debates of the campaign.

With three weeks remaining until the Nov. 4 election day, McCain is struggling under the heavy burden of his association with Republican President George W. Bush — and the blame that attaches to the incumbent Republicans for the crumbling financial markets.

Last week, both McCain and running mate Alaska Gov. Sarah Palin appeared to be trying to shift attention away from the troubles confronting the American voters by issuing stinging attacks on Obama.

Palin opened the series of blistering assaults by accusing Obama of "palling around with terrorists," in reference to William Ayers, a founder of the 1960s violent Weather Underground group. Obama and Ayers, who live in the same Chicago neighborhood, have worked together on community projects in Chicago, but Obama, who was a child during the Weather Underground's violent activities, has denounced Ayers' violent past.

On Sunday, one man shouted out "Obama loves terrorists" as Palin talked about "the bad guys."

The Republican ticket, watching Obama's lead grow in the polls, apparently decided the tactic had proven fruitless and was shifting course back to vows to revamp Washington, blaming politicians and greedy Wall Street executives for the worst financial crisis to face the country in 80 years.

Palin campaigned in southeastern Ohio on Sunday, easing back on attacks but reminding the crowd of Obama's remarks during the primary campaign in which he said working class Americans, afraid for their economic future, were clinging to guns and religion.

Sen. Lindsey Graham, a South Carolina Republican and key McCain adviser, said on Sunday that the candidate was considering a new economic proposal that would include provisions to lower taxes for investors by cutting back the share the government takes from capital gains and dividends.

"It will be a very comprehensive approach to jump-start the economy by allowing capital to be formed easier in America by lowering taxes," Graham said on CBS television.

McCain already has laid out proposals to address the crisis, including a $300 billion plan for the federal government to buy distressed mortgages and renegotiate them at a reduced price for hard-pressed homeowners. He argues the move is necessary to take thousands of bad mortgages off the books to stabilize home values and restart credit flows. Critics say the plan would reward financial institutions that made the bad loans in the first place.

The Arizona senator planned a new speech at a campaign stop in Virginia on Monday in which he will argue he can win the race despite national and battleground state polls showing him trailing Obama.

"The national media has written us off. Senator Obama is measuring the drapes, and planning with Speaker (Nancy) Pelosi and Senator (Harry) Reid to raise taxes, increase spending, take away your right to vote by secret ballot in labor elections, and concede defeat in Iraq. But they forgot to let you decide. My friends, we've got them just where we want them," McCain planned to tell supporters, according to speech excerpts provided by the campaign.

In fact, Obama has proposed tax cuts for those making less than $250,000 and has called for a timetable for withdrawing U.S. forces from Iraq.

Obama, meanwhile, got a further boost Sunday when former President Bill Clinton and his wife, Sen. Hillary Rodham Clinton, made their first joint campaign appearance together on his behalf.

Bill Clinton urged voters to back Obama, who he said would put an end to Republican bumbling that he blamed for the failing economy.

"If you ask yourselves who has the best ideas, who's got the best instincts, who's got the best ability to understand these challenges, who's got the best supporting cast, the answer is Barack Obama," the former president said.

Hillary Clinton introduced Obama's running mate, Delaware Sen. Joe Biden, at the Sunday rally in working-class Scranton, Pennsylvania, a city that has taken on outsized symbolism for Democrats this year. It was Biden's birthplace and Hillary Clinton's father grew up and is buried there.

Her spirited remarks were repeatedly interrupted by applause from thousands of supporters as she delivered one-liners attacking Bush and McCain. At one point she said Republicans viewed middle class Americans not as "fundamental, but ornamental" to the functioning of the U.S. economy.

Biden hammered McCain as the candidate who would only bring the country four more years of Bush administration policies, dismissing both men as unable to deal with the failing economy. He charged McCain with trying to distract Americans from their economic woes by launching "unbecoming personal attacks" on Obama.