Though the issue of campaign attacks drew attention, it was not the first point in the debate where the candidates clashed. After another dismal day on Wall Street, McCain and Obama began the debate by discussing how each of their plans would best relieve the pressure on ordinary Americans.
Obama stressed a "rescue plan for the middle class," and McCain pushed his plan to buy bad mortgages from struggling families.
McCain said his mortgage plan would help "reverse this continued decline in home ownership" -- but Obama called the plan a potential "giveaway to banks."
Both candidates said taxes need to be cut, but diverged on who would best benefit from a break.
McCain cited the case of "Joe the plumber," a small business owner who confronted Obama on the campaign trail this past week, and would not be eligible for tax cuts under Obama's proposal because he earned more than $250,000 per year. McCain said Obama's tax plan fostered "class warfare."
Outside Toledo, Ohio, Sunday, Obama was approached by "Joe the plumber," who actually goes by the name Joe Wurzelbacher, a big, bald man with a goatee who asked Obama if he believes in the American dream.
"We're gonna take Joe's money, give it to Sen. Obama and let him spread the wealth around," McCain said. "Why would you want to increase anybody's taxes right now?"
Obama countered by suggesting tax cuts for the wealthy were "the centerpiece" of McCain's tax proposals.
"Tax policy is a major difference between Sen. McCain and myself," Obama said. "We both want to cut taxes, but differ on who we want to cut taxes for. Sen. McCain wants to cut taxes for some of the biggest companies in America."
As the discussion moved to how to cut spending, McCain got in an early zinger.
In an effort to rebut Obama's continued efforts to tie his policies to the unpopular incumbent president, McCain said, "I am not President Bush. If you wanted to run against President Bush, you should have run four years ago."
Obama responded, "Occasionally, I have mistaken your policies for George Bush' s policies because, on the core economic issues ... you have been a vigorous supporter of President Bush. You've shown commendable independence on some key issues, like torture, for instance, and I give you enormous credit. But essentially, what you're proposing is eight more years of the same thing."
Later in the debate, the candidates tangled on the hot-button issue of abortion.
Though Obama and McCain disagreed on whether they believed the historic Supreme Court decision on abortion, Roe v. Wade, was right, they both said they would not use abortion as a "litmus test" for choosing potential nominees to the court.
"I have never imposed a litmus test on anyone," McCain said. "I thought [Roe] was a bad decision. I think the decision should rest in the hands of the states. I believe we should have nominees based on qualifications rather than litmus test."
McCain also accused Obama of being out of touch with the "views of mainstream America" by refusing to oppose legislation aimed at late-term, or partial-birth, abortion during his time in the Illinois State Senate.