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.
"Let me talk to you about an important aspect of this issue: We have to change the culture of America -- show courage and compassion," McCain said. "Obama, as a member of the Illinois State Senate, voted against a law that would provide immediate medical attention to a child. He voted present on another vote where he voted against a ban on partial-birth abortion. I don't know how you vote present on some of that. That's his record, and that's a matter of his record. ... It was clear-cut votes that Obama voted in direct contradiction to the feelings and views of mainstream America."
Obama said he opposed legislation calling for a ban on late-term abortions because there was no exception to protect the life of the mother.
"If it sounds incredible that I would vote to withhold life-saving treatment from an infant, it's because it's not true," Obama said. "I support a ban on late-term abortions as long as there's an exception for a mother's health and life, and there was no exception. That was rejected and that's why I voted present. I'm willing to support such a bill as long as there's that exception."