But Kerry did not give any ground, opening the debate by reminding the audience at Washington University in St. Louis, and millions watching on television, that weapons of mass destruction had not been found in Iraq -- Bush's principal justification for going to war. He also said Bush was the first president in 72 years to lose jobs and solemnly promised that, if elected, he would not raise taxes on people making less than $200,000 a year.

Friday's debate was feisty, with both candidates turning up the heat since their first debate last week at the University of Miami. The looser rules of the town hall style debate format allowed the candidates to walk around the stage and challenge each other's assertions.

The debate, which featured domestic and foreign policy questions from voters in attendance, included discussions and sometimes heated exchanges on issues ranging from the war in Iraq to foreign policy on Iran and North Korea to the military draft. It also showcased the candidates' differing views on the Patriot Act, embryonic stem cell research and abortion.

"You know, for a while [Kerry] was a strong supporter of getting rid of Saddam Hussein," Bush said, during the 90-minute debate. "He saw the wisdom -- until the Democrat primary came along and Howard Dean, the anti-war candidate, began to gain on him, and he changed positions.

"I don't see how you can lead this country in a time of war, in a time of uncertainty, if you change your mind because of politics."

In his first comment, Kerry said Bush simply could not defend his record as president.

"The president didn't find weapons of mass destruction in Iraq, so he's really turned his campaign into a weapon of mass deception," Kerry said. "And the result is that you've been bombarded with advertisements suggesting that I've changed a position on this or that or the other."

The debate also featured some humor, with Bush answering a question about whom he would choose for a hypothetical Supreme Court appointment by saying, "I'm not telling." Kerry and Bush also joked at the end of the debate over who should issue their closing statements first -- an order pre-determined by a coin toss.