Oct. 16 (Bloomberg) -- Republican presidential nominee John McCain used his final debate with Democrat Barack Obama to attack his rival over taxes, spending and past associations, while Obama countered by stressing his approach to the economic and health- care issues that dominate voters' concerns.

McCain, 72, trailing in most polls, took the offensive almost from the first moments of the debate at Hofstra University in Hempstead, New York, last night.

He portrayed Obama as a tax-and-spend Democrat whose policies would damage small businessmen -- including would-be Ohio entrepreneur Joe Wurzelbacher. McCain repeatedly invoked him, calling him ``Joe the plumber,'' triggering a debate-within- a-debate over which candidate was on Joe's side.

``Joe wants to buy the business that he has been in for all of these years, worked 10, 12 hours a day,'' McCain said. ``And he wanted to buy the business, but he looked at your tax plan and he saw that he was going to pay much higher taxes.''

Obama, 47, kept his focus on his contention that McCain would continue the economic policies of President George W. Bush. That led McCain to retort that Obama was running against the wrong opponent.

``Senator Obama, I am not President Bush,'' he said. ``If you wanted to run against President Bush, you should have run four years ago.''

Obama replied that while his opponent has shown ``commendable independence'' from Bush on some issues, he had failed to do so on the economy.

``You have been a vigorous supporter of President Bush,'' Obama said. ``When it comes to economic policies, essentially what you're proposing is eight more years of the same thing.''

Last Opportunity

The debate was one of McCain's last opportunities to reverse the momentum that has been running in Obama's direction in recent weeks. In the middle of a financial crisis, Americans say they trust Obama more to handle the economy, and the Illinois senator leads McCain 50 percent to 41 percent in a new Bloomberg/Los Angeles Times poll.

McCain may not have achieved what he needed, according to two snap surveys. A CBS News poll of 638 voters who hadn't committed to a candidate before the debate found that 53 percent judged Obama the winner; 22 percent picked McCain. A CNN poll of 620 adults found Obama won by a margin of 58 percent to 31 percent. Polls showed viewers of the first two debates considered Obama the winner in those face-offs as well.

No Knockout

``What John McCain needed was a knockout blow, and he didn't have one,'' said Ross Baker, a political science professor at Rutgers University in New Brunswick, New Jersey. ``He probably had the best line of the night when he said Obama should have run in 2004 if he wanted to run against George Bush.'' Still, Baker said, ``it wasn't a stunner.''

Wurzelbacher's star turn in the debate stemmed from his Oct. 12 encounter with Obama while the candidate knocked on doors in a neighborhood outside Toledo, Ohio. He challenged Obama over the candidate's plan to raise taxes on incomes above $250,000 annually, saying that would also hit small businesses and make it harder for him to fulfill his goal of buying a plumbing business that may make more than $250,000 a year.

``Joe, I want to tell you, I'll not only help you buy that business that you worked your whole life for,'' McCain said, staring straight into the camera. ``I'll keep your taxes low and I'll provide available and affordable health care for you and your employees.''

Cutting Taxes

Obama replied that he wanted to cut taxes for 95 percent of working Americans and 98 percent of small businesses, while McCain favored $200 billion in additional tax breaks to some of the wealthiest corporations in America.

``I'm happy to talk to you, Joe, too, if you're out there,'' Obama said.

Douglas Holtz-Eakin, a senior economic adviser to McCain, told Bloomberg Television after the debate that his candidate's use of Joe the plumber ``put a face'' on a vision for America.

Kathleen Hall Jamieson, director of the Annenberg Public Policy Center at the University of Pennsylvania in Philadelphia, agreed, saying his mention of the plumber allowed McCain to take ``control of the debate.''

McCain at first passed up an opportunity to raise questions about Obama's relationship with William Ayers, a 1960s radical who is now a professor at the University of Illinois in Chicago. McCain's running mate, Alaska Governor Sarah Palin, hammered Obama on that subject last week.

`Need to Know'

When Obama cited Palin's comment as an example of ``not talking about issues,'' McCain finally engaged. ``We need to know the full extent of that relationship,'' he said.

Ayers was indicted on charges of conspiring to commit bombings as part of the Weather Underground group and spent 10 years as a fugitive. The charges were later dropped because of prosecutorial misconduct.

Obama served on the board of a Chicago charitable foundation with Ayers and attended a political event at Ayers's house during his first run for the Illinois state Senate.

He repeated his condemnation of Ayers's ``despicable acts'' in the 1960s, then told McCain: ``The fact that this has become such an important part of your campaign, Senator McCain, says more about your campaign than it says about me.''

`Break Your Heart'

Obama repeatedly brought up the issue of health care as he and McCain sparred on other topics. When both got a question on the subject from moderator Bob Schieffer of CBS News, Obama talked about how he hears from people all over the country in ways that ``will break your heart.'' He said his plan would both control costs and increase coverage.

McCain talked about ways of reducing costs such as putting information online. He claimed Obama would set up ``health care bureaucracies'' in the country.

The two candidates opened the debate talking about the economic crisis and the government's response, led by Treasury Secretary Henry Paulson. They met after a day in which the Dow Jones Industrial Average dropped 7.9 percent amid concerns that government plans to stabilize financial markets won't alleviate the credit crunch or prevent the economic slump from deepening.

McCain said he's unhappy that federal policy makers aren't moving to adopt his $300 billion proposal to buy bad mortgages.

``We've got to put the homeowners first,'' the Arizona senator said. ``I am disappointed that Secretary Paulson and others have not made that their first priority.''

`Giveaway to Banks'

Obama said he agrees that homeowners need help, while opposing the way McCain would handle the situation. ``It could be a giveaway to banks,'' Obama said.

Both said they wouldn't use a litmus test for Supreme Court nominations, even as they disagreed over the issue of abortion and Roe v. Wade, the 1973 high court decision that legalized the practice.

``I thought it was a bad decision,'' McCain said. ``I think that decisions should rest in the hands of the states. I'm a federalist.''

Obama said decisions about Supreme Court justices will be among the most ``consequential'' for the next president.

``Roe v. Wade probably hangs in the balance,'' Obama said. While saying that ``good people'' can disagree, he said he believes it's a woman's choice. ``The Constitution has a right to privacy in it that shouldn't be subject to state referendum any more than our First Amendment rights are subject to state referendum.''

Late in the debate, Obama passed up a chance, offered by Schieffer, to criticize the qualifications of McCain's running mate to be president.

``That's going to be up to the American people,'' he said of Palin. He called her capable and noted her popularity with the base of the Republican Party.

To contact the reporters on this story: Ken Fireman in Washington at kfireman1@bloomberg.net; Kristin Jensen in Washington at kjensen@bloomberg.net

Last Updated: October 16, 2008 01:09 EDT