Another dozen or so questions were asked by a group of 80 undecided voters from the Nashville area selected by the Gallup Poll.
McCain favors the town hall format and had previously challenged Obama to other town hall debates, a fact that led to the evening's first zinger.
"It's good to be with you at a town hall meeting," McCain said to Obama, who refused McCain's invitation to meet for weekly town-hall debates.
But the town hall style never fully took off, with the candidates rarely engaging the audience or each other and Brokaw chiding the candidates for not sticking to the time limits.
Asked whom they would nominate as Treasury secretary in their respective administrations, McCain suggested former eBay CEO Meg Whitman, while Obama suggested Berkshire Hathaway CEO Warren Buffett.
Both took the opportunity to blame each other for playing a role in causing the economic crisis.
McCain accused Obama of receiving donations from individuals at Fannie Mae and Freddie Mac, the mortgage giants whose failures signaled the oncoming financial crisis.
"The real catalyst was Fannie and Freddie. They're the ones who were the encouragement of Sen. Obama and his cronies that went out and made all these risky loans, gave them to all these people who couldn't pay back. There were some of us who stood up and said we needed to enact legislation," McCain said.
"There were some of us who stood up against this," he said. "There were others who took a hike."
Obama has received $126,349 -- $120,349 from employees and $6,000 from Political Action Committees or PACs -- since he joined the Senate in 2005, according to the Center for Responsive Politics. His total is the second largest of any member of Congress, right behind Sen. Chris Dodd, D-Conn., at $165,400.
McCain has received $21,550 from employees (nothing from PACs) since 1989 -- a period 14 years longer than Obama has been in the Senate -- according to the Center for Responsive Politics.
Obama said he was the real reformer of the two, who had called Treasury Secretary Henry Paulson and Federal Reserve System chairman Ben Bernanke to take action while McCain was waiting for the free market to correct itself.
"I've got to correct McCain's history, not surprisingly. Deregulation of the financial system. McCain, as recently as March, bragged about the fact that he's a deregulator. Two years ago I said there was a subprime crisis we had to deal with. I wrote to Paulson and Bernanke and told them it's something we need to deal with. I never promoted Fannie Mae."
Then Obama switched tacks, speaking directly to Oliver Clark, the audience member who had asked a question about the bailout, saying, "You're not interested in politicians pointing fingers. You're interested in the impact on you. This is not the end, this is the beginning of the process."
Asked whether that meant he thought the economy was poised to get much worse, Obama said, "I am confident about the American economy, but we are going to have to have to leadership from Washington."
The two men clashed over whether the U.S. military should make cross-border excursions into Pakistan to fight suspected militants, offering different perspectives on how the United States should flex its might and turning the issue into a question of leadership.
McCain accused Obama of pandering and emboldening American enemies by announcing he would use his military strikes in advance.