The latest report on Iraq's prewar weapons capacity produced a fiery exchange between President Bush and John F. Kerry on Thursday, with Bush asserting the report showed that Saddam Hussein was a danger even in the absence of weapons of mass destruction and Kerry charging that Bush had inflated the threat and was blind to evidence proving the war was a mistake.

In a preview of what Americans are likely to see in Friday's second presidential debate, Bush said the report by chief U.S. weapons inspector Charles A. Duelfer, while concluding that Hussein possessed no such weapons at the time of the war, revealed that the former Iraqi leader hoped to manipulate the international community into ending sanctions with the intent of restarting his weapons programs.

"He retained the knowledge, the materials, the means and the intent to produce weapons of mass destruction," Bush said. "And he could have passed that knowledge on to our terrorist enemies. . . . In a world after September the 11th, he was a threat we had to confront. And America and the world are safer for our actions."

Kerry responded two hours later with some of the most contemptuous language he has used against the president and Vice President Cheney during their bitter campaign. He said the administration had "aggrandized and fictionalized" the threat posed by Hussein in the run-up to the war, was unprepared for the war's aftermath and remained intransigent now that prewar intelligence has been undermined by a series of inspection reports.

"Ladies and gentlemen," he said here, "the president of the United States and the vice president of the United States may well be the last two people on the planet who won't face the truth about Iraq."

The Duelfer report transformed what might otherwise have been a relatively quiet day on the campaign trail in which Bush and Kerry were preparing to fly to St. Louis for their debate, which will begin at 9 p.m. Eastern time. The report's reverberations were felt well beyond the campaign trail, triggering a renewed debate about whether Hussein was being adequately contained by means other than war or whether removing him and his regime by force was necessary to defuse a potentially serious threat.

David Kay, who preceded Duelfer as the chief U.S. weapons inspector, said the latest report clearly shows that Hussein was not a threat to the United States. "Look, Saddam was delusional," Kay said on NBC's "Today" show Thursday. "He had a lot of intent. He didn't have capabilities. Intent without capabilities is not an imminent threat."

But Sen. Orrin G. Hatch (R-Utah) agreed with Bush's assessment of the report, telling CNN that it "says that there's no question that Saddam Hussein was going to try to get rid of the sanctions so he could resuscitate his program of weapons of mass destruction. I think the president has done exactly what he should have done."

With newspaper headlines and television news programs highlighting the report's conclusion that the 1991 Persian Gulf War and subsequent inspections by the United Nations had eliminated Hussein's illicit weapons programs, a finding that undercut Bush's principal rationale for going to war, the president and Cheney went on the offensive early Thursday.

Cheney was first to speak, saying at a campaign event in Miami that the Duelfer report, far from undermining the administration's rationale for going to war, actually bolstered its case. He said it showed that Hussein had tried to corrupt the United Nations oil-for-food program in an effort to buy off foreign governments to win an end to the sanctions that were imposed after the Gulf War ended. Hussein's goal, Cheney said, was to start producing weapons of mass destruction.

"Delay, defer, wait wasn't an option," he said.

Bush then went before the cameras outside the White House before leaving Washington for a campaign event in Wisconsin. He acknowledged the breakdown in U.S. and other intelligence, which had overstated Hussein's weapons capacity, but held firm to his argument that the former Iraqi leader remained a menace who would have aided and abetted terrorists, if given the chance.

"The Duelfer report showed that Saddam was systematically gaming the system, using the U.N. oil-for-food program to try to influence countries and companies in an effort to undermine sanctions," Bush said. "He was doing so with the intent of restarting his weapons program, once the world looked away."

Kerry, speaking outside the suburban Denver hotel where he has been preparing for Friday's debate, then unloaded on the administration, throwing the Duelfer report and the words of L. Paul Bremer, the civilian administrator in Iraq after the invasion, back at the president to argue that he has systematically misled the country and should be replaced.

"Ambassador Bremer finally said what John Edwards and I have been saying for months: President Bush's decision to send in too few troops, without thinking about what would happen after the initial fighting was over, has left our troops more vulnerable, left the situation on the ground in chaos and made the mission in Iraq much more difficult to accomplish," he said. "That is the truth."

Kerry lambasted national security adviser Condoleezza Rice for suggesting that the president would have sent in more troops if commanders in Iraq had asked, calling that an abdication of "the buck stops here" responsibility of the commander in chief. "For President Bush, it's always someone else's fault -- denial, and blaming someone else," he said.

Saying Bush was in "absolute full-spin mode," Kerry accused the administration of earlier using discredited pieces of evidence, "like aluminum tubes and Niger yellowcake uranium" to inflate the threat from Hussein and shift the focus from what he called the real enemy, al Qaeda and Osama bin Laden, and of changing rationales now. "My fellow Americans, you don't make up or find reasons to go to war after the fact," he said.

Kerry's running mate, Sen. John Edwards (N.C.), ridiculed the administration's arguments during a campaign rally in Bayonne, N.J., accusing Cheney of convoluted logic and asserting: "Here's the truth: The vice president, Dick Cheney, and the president, George W. Bush, need to recognize that the Earth is actually round. That the sun rises in the east. . . . They need to level with the American people."

The sparring continued throughout the day. Campaigning in Wisconsin, Bush fired back at Kerry, quoting the Massachusetts senator as saying earlier that Hussein had an arsenal of weapons of mass destruction, that he might develop a nuclear weapon, reinvade Kuwait, threaten Israel or pass weapons to terrorists.

Kerry made those statements in 2002 in explaining why he supported the resolution authorizing Bush to go to war, the president said, adding: "Now today, my opponent tries to say that I made up reasons to go to war. Just who is the one trying to mislead the American people?"

But Kerry advisers said Bush had left out part of what Kerry said in that statement, including the assertion that regime change by itself was not a justification for war, particularly unilaterally, unless there was no other way to disarm Hussein.

Kerry was asked at his news conference how he could accuse Bush of "aggrandizing" the threat Hussein posed when he also had claimed the Iraqi leader was dangerous and needed to be confronted. Kerry said that effective diplomacy could have kept sanctions in place and Hussein contained. "The point is, there are all kinds of options available to a president to deal with threats," he said. "And I consistently laid out to the president how to deal with Saddam Hussein, who was a threat."

Staff writers Ovetta Wiggins, traveling with Cheney; Paul Farhi, traveling with Bush; and Chris L. Jenkins, traveling with Edwards, contributed to this report.

Kerry walks with campaign volunteers Ruth Steiner, foreground, and Pat Bandich outside the Inverness Hotel in Englewood, Colo., where he has been preparing for his face-off with Bush.President Bush greets a supportive crowd at a rally in Wausau, Wis. His second showdown with presidential challenger John F. Kerry will be held tonight in St. Louis.